[client] Pre-seed CustomActivator CLSID under HKCU AppUserModelId\NetBird

The Wails notifications service reads HKCU\Software\Classes\AppUserModelId\
<AppName>\CustomActivator on first startup; if present it uses that GUID
as the toast activator CLSID, otherwise it generates a fresh UUID and
writes it back. Without an installer-supplied value the per-machine GUID
diverges from the ToastActivatorCLSID baked into the Start Menu and
Desktop shortcuts, and the COM activator never fires when a toast is
clicked. Seed the same CLSID the shortcuts use so the two sides match.

.github/DISCUSSION_TEMPLATE/ideas-feature-requests.yml

@@ -1,130 +0,0 @@
-body:
-  - type: markdown
-    attributes:
-      value: |
-        ## Ideas & Feature Requests
-
-        Use this category for feature requests, enhancements, integrations, and product ideas.
-
-        NetBird uses community traction in discussions — upvotes, replies, affected users, and use-case detail — as an input when deciding what should become a maintainer-curated issue or roadmap item. A clear problem statement is more useful than a solution-only request.
-
-        Please search first and add your use case to an existing discussion when one already exists.
-
-  - type: checkboxes
-    id: preflight
-    attributes:
-      label: Before posting
-      options:
-        - label: I searched existing discussions and issues for similar requests.
-          required: true
-        - label: I checked the documentation to confirm this is not already supported.
-          required: true
-        - label: This is a product idea or enhancement request, not a support question.
-          required: true
-        - label: I removed or anonymized sensitive details from examples and screenshots.
-          required: true
-
-  - type: dropdown
-    id: area
-    attributes:
-      label: Product area
-      description: Select every area this request touches.
-      multiple: true
-      options:
-        - Client / Agent
-        - CLI
-        - Desktop UI
-        - Mobile app
-        - Dashboard / Admin UI
-        - Management service / API
-        - Signal service
-        - Relay
-        - DNS
-        - Routes / Exit nodes
-        - NetBird SSH
-        - Access control policies
-        - Posture checks
-        - Identity provider / SSO
-        - Self-hosting / Deployment
-        - Kubernetes / Operator
-        - Terraform / Automation
-        - Documentation
-        - Other / not sure
-    validations:
-      required: true
-
-  - type: textarea
-    id: problem
-    attributes:
-      label: Problem or use case
-      description: What are you trying to accomplish, and what is difficult or impossible today?
-      placeholder: |
-        As a ...
-        I want to ...
-        Because ...
-    validations:
-      required: true
-
-  - type: textarea
-    id: proposal
-    attributes:
-      label: Proposed solution
-      description: Describe the behavior, workflow, API, UI, or integration you would like to see.
-    validations:
-      required: true
-
-  - type: textarea
-    id: alternatives
-    attributes:
-      label: Alternatives or workarounds considered
-      description: What have you tried today? Why is the current workaround not enough?
-
-  - type: textarea
-    id: impact
-    attributes:
-      label: Community impact and priority
-      description: Help us understand who benefits and how urgent this is.
-      placeholder: |
-        - Number of users/teams/peers affected:
-        - Deployment type: Cloud / self-hosted / both
-        - Frequency: daily / weekly / occasional
-        - Blocking production adoption? yes/no
-        - Related comments, discussions, or customer requests:
-    validations:
-      required: true
-
-  - type: textarea
-    id: examples
-    attributes:
-      label: Examples from other tools or products
-      description: If another tool solves this well, link or describe the behavior.
-
-  - type: textarea
-    id: security
-    attributes:
-      label: Security, privacy, and compatibility considerations
-      description: Note any access-control, audit, data retention, network, platform, or backward-compatibility concerns.
-
-  - type: textarea
-    id: implementation
-    attributes:
-      label: Implementation ideas
-      description: Optional. If you are familiar with the codebase or API, share possible implementation notes.
-
-  - type: dropdown
-    id: contribution
-    attributes:
-      label: Are you willing to help?
-      options:
-        - Yes, I can submit a PR if the approach is accepted.
-        - Yes, I can test or validate a proposed implementation.
-        - Yes, I can provide more use-case details.
-        - Not at this time.
-    validations:
-      required: true
-
-  - type: textarea
-    id: additional-context
-    attributes:
-      label: Additional context
-      description: Add screenshots, diagrams, links, or anything else that helps explain the request.

.github/DISCUSSION_TEMPLATE/issue-triage.yml

@@ -1,237 +0,0 @@
-body:
-  - type: markdown
-    attributes:
-      value: |
-        ## Issue Triage
-
-        Use this category for reproducible bugs and regressions in NetBird.
-
-        The more context you include, the faster we can validate and act on your report. If you're not sure whether something is a bug, **Q&A / Support** is a good starting point — we can always move the conversation here once we've confirmed it's a product issue.
-
-        Intermittent issues are useful too. Include the trigger, frequency, timing, and any logs or debug evidence you have, and we'll work from there.
-
-        Please don't include secrets, tokens, private keys, internal hostnames, or public IPs. Security vulnerabilities should be reported through the repository security policy rather than a public discussion.
-
-  - type: checkboxes
-    id: preflight
-    attributes:
-      label: Before posting
-      options:
-        - label: I searched existing discussions and issues, including closed ones, and checked the relevant docs.
-          required: true
-        - label: I believe this is a product bug rather than a configuration or setup question.
-          required: true
-        - label: I can reproduce this issue, or for intermittent issues I've included trigger, frequency, and timing details below.
-          required: true
-        - label: I removed or anonymized sensitive data from logs, screenshots, and configuration.
-          required: true
-
-  - type: dropdown
-    id: area
-    attributes:
-      label: Affected area
-      description: Select every area this report touches.
-      multiple: true
-      options:
-        - Client / Agent
-        - Reverse Proxy
-        - CLI
-        - Desktop UI
-        - Mobile app
-        - Peer connectivity
-        - DNS
-        - Routes / Exit nodes
-        - NetBird SSH
-        - Relay / Signal / NAT traversal
-        - Login / Authentication / IdP
-        - Dashboard / Admin UI
-        - Management service / API
-        - Access control policies / Posture checks
-        - Self-hosting / Deployment
-        - Kubernetes / Operator
-        - Documentation
-        - Other / not sure
-    validations:
-      required: true
-
-  - type: dropdown
-    id: deployment
-    attributes:
-      label: Deployment type
-      options:
-        - NetBird Cloud
-        - Self-hosted - quickstart script
-        - Self-hosted - advanced/custom deployment
-        - Local development build
-        - Not sure / environment I do not fully control
-    validations:
-      required: true
-
-  - type: dropdown
-    id: platform
-    attributes:
-      label: Operating system or environment
-      description: Select every environment involved in the reproduction.
-      multiple: true
-      options:
-        - Linux
-        - macOS
-        - Windows
-        - Android
-        - iOS
-        - FreeBSD
-        - OpenWRT
-        - Docker
-        - Kubernetes
-        - Synology
-        - Browser
-        - Other / not sure
-    validations:
-      required: true
-
-  - type: textarea
-    id: version
-    attributes:
-      label: NetBird version and upgrade status
-      description: Run `netbird version` where applicable. For self-hosted deployments, include management, signal, relay, and dashboard versions if available. If you cannot test on a current/supported version, explain why.
-      placeholder: |
-        Example:
-        - Client: 0.30.2
-        - Management: 0.30.2
-        - Signal: 0.30.2
-        - Relay: 0.30.2
-        - Dashboard: 0.30.2
-        - Upgrade status: reproduced on current version / cannot upgrade because ...
-    validations:
-      required: true
-
-  - type: dropdown
-    id: regression
-    attributes:
-      label: Did this work before?
-      options:
-        - Yes, this worked before
-        - No, this never worked
-        - Not sure
-    validations:
-      required: true
-
-  - type: textarea
-    id: regression-details
-    attributes:
-      label: Regression details
-      description: If this worked before, include the last known working version, first known broken version, and any recent upgrade, configuration, network, or IdP changes.
-      placeholder: |
-        - Last known working version:
-        - First known broken version:
-        - Recent changes:
-
-  - type: textarea
-    id: summary
-    attributes:
-      label: Summary
-      description: Briefly describe the reproducible bug.
-      placeholder: What is broken?
-    validations:
-      required: true
-
-  - type: textarea
-    id: current-behavior
-    attributes:
-      label: Current behavior
-      description: What happens now? Include exact errors, timeouts, UI messages, or failed commands when possible.
-    validations:
-      required: true
-
-  - type: textarea
-    id: expected-behavior
-    attributes:
-      label: Expected behavior
-      description: What did you expect to happen instead?
-    validations:
-      required: true
-
-  - type: textarea
-    id: reproduction
-    attributes:
-      label: Steps to reproduce
-      description: Provide the smallest set of steps that reliably reproduces the bug. If the issue is intermittent, include the trigger, frequency, timing, and relevant timestamps.
-      placeholder: |
-        1. Configure ...
-        2. Run ...
-        3. Observe ...
-
-        For intermittent issues:
-        - Trigger:
-        - Frequency:
-        - Timing/timestamps:
-    validations:
-      required: true
-
-  - type: textarea
-    id: environment
-    attributes:
-      label: Environment and topology
-      description: Include the relevant topology and software involved in the reproduction. For UI/docs-only reports, write `N/A` if this does not apply. Use `None`, `Unknown`, or `N/A` where appropriate.
-      placeholder: |
-        - Peer A:
-        - Peer B:
-        - Same LAN or different networks:
-        - NAT/CGNAT/corporate firewall/mobile network:
-        - Other VPN software:
-        - Firewall, DNS, or endpoint security software:
-        - Routes, DNS, policies, posture checks, or SSH rules involved:
-        - IdP, reverse proxy, or browser involved:
-    validations:
-      required: true
-
-  - type: textarea
-    id: self-hosted-details
-    attributes:
-      label: Self-hosted details, if available
-      description: Optional. If you use self-hosting and have access to these details, include them. If you do not administer the environment, provide what you know and say what you cannot access.
-      placeholder: |
-        - Deployment method: quickstart / Docker Compose / Helm / operator / custom
-        - Management/signal/relay/dashboard versions:
-        - Reverse proxy:
-        - IdP/provider:
-        - STUN/TURN/coturn/relay details:
-        - Relevant component logs:
-
-  - type: textarea
-    id: logs
-    attributes:
-      label: Logs, status output, or debug evidence
-      description: |
-        For client, connectivity, DNS, route, relay/signal, or self-hosted reports, logs are essential — please include anonymized output from `netbird status -dA`, or a debug bundle via `netbird debug for 1m -AS -U`. Debug bundles are automatically deleted after 30 days.
-
-        For UI, dashboard, or documentation reports, leave the pre-filled `N/A`.
-      value: "N/A"
-      render: shell
-    validations:
-      required: true
-
-  - type: textarea
-    id: related-reports
-    attributes:
-      label: Related issues or discussions
-      description: Optional. Link similar reports you found while searching, if any.
-      placeholder: |
-        - Related issue/discussion:
-        - Why this may be the same or different:
-
-  - type: textarea
-    id: impact
-    attributes:
-      label: Impact
-      description: Optional. Help us understand priority. How many users, peers, environments, or workflows are affected? Is there a workaround?
-      placeholder: |
-        - Affected users/peers:
-        - Business or production impact:
-        - Workaround available:
-
-  - type: textarea
-    id: additional-context
-    attributes:
-      label: Additional context
-      description: Add links to related discussions, issues, docs, screenshots, recordings, or anything else that may help validation.

.github/DISCUSSION_TEMPLATE/q-a-support.yml

@@ -1,146 +0,0 @@
-body:
-  - type: markdown
-    attributes:
-      value: |
-        ## Q&A / Support
-
-        Use this category for questions about configuration, setup, self-hosted deployments, troubleshooting, and general NetBird usage.
-
-        This is community support and does not provide an SLA. For NetBird Cloud support, use the official support channel linked from the issue creation page. Please do not post secrets, tokens, private keys, internal hostnames, or public IPs unless you intentionally want them public.
-
-        If your question turns into a reproducible product defect, DevRel or a maintainer may ask you to open or move the conversation to Issue Triage.
-
-  - type: checkboxes
-    id: preflight
-    attributes:
-      label: Before posting
-      options:
-        - label: I searched existing discussions and issues for similar questions.
-          required: true
-        - label: I reviewed the relevant NetBird documentation or troubleshooting guide.
-          required: true
-        - label: I removed or anonymized sensitive data from logs, screenshots, and configuration.
-          required: true
-
-  - type: dropdown
-    id: topic
-    attributes:
-      label: Topic
-      multiple: true
-      options:
-        - Getting started
-        - Self-hosting
-        - Client / Agent
-        - CLI
-        - Desktop UI
-        - Mobile app
-        - Dashboard / Admin UI
-        - DNS
-        - Routes / Exit nodes
-        - NetBird SSH
-        - Relay
-        - Access control policies
-        - Posture checks
-        - Identity provider / SSO
-        - API
-        - Kubernetes / Operator
-        - Terraform / Automation
-        - Documentation
-        - Other / not sure
-    validations:
-      required: true
-
-  - type: dropdown
-    id: deployment
-    attributes:
-      label: Deployment type
-      options:
-        - NetBird Cloud
-        - Self-hosted - quickstart script
-        - Self-hosted - advanced/custom deployment
-        - Local development build
-        - Not sure
-    validations:
-      required: true
-
-  - type: dropdown
-    id: platform
-    attributes:
-      label: Operating system or environment
-      multiple: true
-      options:
-        - Linux
-        - macOS
-        - Windows
-        - Android
-        - iOS
-        - FreeBSD
-        - OpenWRT
-        - Docker
-        - Kubernetes
-        - Synology
-        - Browser
-        - Other / not sure
-    validations:
-      required: true
-
-  - type: input
-    id: version
-    attributes:
-      label: NetBird version
-      description: Run `netbird version` where applicable. For self-hosted deployments, include component versions if relevant.
-      placeholder: "Example: client 0.30.2, management 0.30.2"
-
-  - type: textarea
-    id: question
-    attributes:
-      label: Question
-      description: What are you trying to understand or accomplish?
-      placeholder: Describe your question clearly.
-    validations:
-      required: true
-
-  - type: textarea
-    id: goal
-    attributes:
-      label: Desired outcome
-      description: What would a successful answer help you do?
-      placeholder: |
-        I want to configure ...
-        I expected ...
-        I need help deciding ...
-
-  - type: textarea
-    id: attempted
-    attributes:
-      label: What have you tried?
-      description: Include commands, documentation links, configuration attempts, or troubleshooting steps already tried.
-      placeholder: |
-        - Read ...
-        - Ran ...
-        - Changed ...
-        - Observed ...
-
-  - type: textarea
-    id: environment
-    attributes:
-      label: Relevant environment details
-      description: Include redacted topology, IdP/provider, reverse proxy, firewall, DNS, route, policy, or self-hosted setup details that may affect the answer.
-      placeholder: |
-        - Deployment:
-        - Components involved:
-        - Network/topology:
-        - Related config:
-
-  - type: textarea
-    id: logs
-    attributes:
-      label: Logs or output
-      description: Optional. Include anonymized logs, command output, screenshots, or `netbird status -dA` if relevant.
-      render: shell
-
-  - type: textarea
-    id: additional-context
-    attributes:
-      label: Additional context
-      description: Add links, diagrams, screenshots, or other details that may help the community answer.

.github/ISSUE_TEMPLATE/bug-issue-report.md

@@ -0,0 +1,71 @@
+---
+name: Bug/Issue report
+about: Create a report to help us improve
+title: ''
+labels: ['triage-needed']
+assignees: ''
+
+---
+
+**Describe the problem**
+
+A clear and concise description of what the problem is.
+
+**To Reproduce**
+
+Steps to reproduce the behavior:
+1. Go to '...'
+2. Click on '....'
+3. Scroll down to '....'
+4. See error
+
+**Expected behavior**
+
+A clear and concise description of what you expected to happen.
+
+**Are you using NetBird Cloud?**
+
+Please specify whether you use NetBird Cloud or self-host NetBird's control plane.
+
+**NetBird version**
+
+`netbird version`
+
+**Is any other VPN software installed?**
+
+If yes, which one?
+
+**Debug output**
+
+To help us resolve the problem, please attach the following anonymized status output
+
+  netbird status -dA
+
+Create and upload a debug bundle, and share the returned file key:
+
+  netbird debug for 1m -AS -U
+
+*Uploaded files are automatically deleted after 30 days.*
+
+
+Alternatively, create the file only and attach it here manually:
+
+  netbird debug for 1m -AS
+
+
+**Screenshots**
+
+If applicable, add screenshots to help explain your problem.
+
+**Additional context**
+
+Add any other context about the problem here.
+
+**Have you tried these troubleshooting steps?**
+- [ ] Reviewed [client troubleshooting](https://docs.netbird.io/how-to/troubleshooting-client) (if applicable)
+- [ ] Checked for newer NetBird versions
+- [ ] Searched for similar issues on GitHub (including closed ones)
+- [ ] Restarted the NetBird client
+- [ ] Disabled other VPN software
+- [ ] Checked firewall settings
+

.github/ISSUE_TEMPLATE/config.yml

@@ -1,26 +1,14 @@
-blank_issues_enabled: false
+blank_issues_enabled: true
 contact_links:
-  - name: Start an Issue Triage discussion
-    url: https://github.com/netbirdio/netbird/discussions/new?category=issue-triage
-    about: Report a bug, regression, or unexpected behavior so DevRel can validate it before it becomes an issue.
-  - name: Propose an idea or feature request
-    url: https://github.com/netbirdio/netbird/discussions/new?category=ideas-feature-requests
-    about: Share feature requests, enhancements, and integration ideas for community feedback and prioritization.
-  - name: Ask a Q&A / Support question
-    url: https://github.com/netbirdio/netbird/discussions/new?category=q-a-support
-    about: Get help with setup, configuration, self-hosting, troubleshooting, and general usage.
-  - name: Security vulnerability disclosure
-    url: https://github.com/netbirdio/netbird/security/policy
-    about: Please do not report security vulnerabilities in public issues or discussions.
-  - name: Community Support Forum
+  - name: Community Support
     url: https://forum.netbird.io/
-    about: Community support forum.
+    about: Community support forum
   - name: Cloud Support
     url: https://docs.netbird.io/help/report-bug-issues
-    about: Contact NetBird for Cloud support.
-  - name: Client / Connection Troubleshooting
+    about: Contact us for support
+  - name: Client/Connection Troubleshooting
     url: https://docs.netbird.io/help/troubleshooting-client
-    about: See the client troubleshooting guide for common connectivity issues.
+    about: See our client troubleshooting guide for help addressing common issues
   - name: Self-host Troubleshooting
     url: https://docs.netbird.io/selfhosted/troubleshooting
-    about: See the self-host troubleshooting guide for common deployment issues.
+    about: See our self-host troubleshooting guide for help addressing common issues

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,20 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: ['feature-request']
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.

.github/ISSUE_TEMPLATE/validated_issue.yml

@@ -1,128 +0,0 @@
-name: Validated issue
-description: Maintainer/DevRel only. Create an issue after a discussion has been validated or for internally validated work.
-title: "[Validated]: "
-body:
-  - type: markdown
-    attributes:
-      value: |
-        ## Discussion-first issue policy
-
-        Issues are maintainer-curated work items. Community reports and feature requests should start in [Discussions](https://github.com/netbirdio/netbird/discussions) so DevRel can validate, reproduce, and route them before engineering time is committed.
-
-        Use this form when:
-        - A discussion has been validated and should become actionable work.
-        - A maintainer is opening internally validated work that can bypass the discussion-first flow.
-
-        Issues opened without a relevant validated discussion or maintainer context may be closed and redirected to Discussions.
-
-  - type: checkboxes
-    id: validation-checks
-    attributes:
-      label: Validation checklist
-      options:
-        - label: This issue is linked to a validated discussion, or it is being opened directly by a maintainer.
-          required: true
-        - label: The report has enough context for engineering to act on it without re-triaging from scratch.
-          required: true
-        - label: Sensitive data, secrets, private keys, internal hostnames, and public IPs have been removed or intentionally disclosed.
-          required: true
-
-  - type: dropdown
-    id: issue-type
-    attributes:
-      label: Issue type
-      options:
-        - Bug / Regression
-        - Feature / Enhancement
-        - Documentation
-        - Maintenance / Refactor
-        - Cross-repository coordination
-        - Other
-    validations:
-      required: true
-
-  - type: input
-    id: source-discussion
-    attributes:
-      label: Source discussion
-      description: Link the GitHub Discussion that was validated. Maintainers bypassing the flow can write "Maintainer-created" and explain why below.
-      placeholder: https://github.com/netbirdio/netbird/discussions/1234
-    validations:
-      required: true
-
-  - type: input
-    id: validation-owner
-    attributes:
-      label: Validation owner
-      description: GitHub handle of the DevRel team member or maintainer who validated this work.
-      placeholder: "@username"
-    validations:
-      required: true
-
-  - type: dropdown
-    id: target-repository
-    attributes:
-      label: Target repository
-      description: Where should the implementation work happen?
-      options:
-        - netbirdio/netbird
-        - netbirdio/dashboard
-        - netbirdio/kubernetes-operator
-        - netbirdio/docs
-        - Multiple repositories
-        - Unknown / needs routing
-    validations:
-      required: true
-
-  - type: textarea
-    id: summary
-    attributes:
-      label: Summary
-      description: Concise description of the validated work.
-      placeholder: What needs to be fixed, changed, documented, or built?
-    validations:
-      required: true
-
-  - type: textarea
-    id: evidence
-    attributes:
-      label: Validation evidence
-      description: For bugs, include reproduction status, affected versions, logs, and environment. For features, include community traction, affected users, and alignment notes.
-      placeholder: |
-        - Reproduced by:
-        - Affected versions / platforms:
-        - Community signal:
-        - Related logs or screenshots:
-    validations:
-      required: true
-
-  - type: textarea
-    id: scope
-    attributes:
-      label: Proposed scope
-      description: Describe what is in scope and, if helpful, what is explicitly out of scope.
-      placeholder: |
-        In scope:
-        - ...
-
-        Out of scope:
-        - ...
-    validations:
-      required: true
-
-  - type: textarea
-    id: acceptance-criteria
-    attributes:
-      label: Acceptance criteria
-      description: What must be true for this issue to be closed?
-      placeholder: |
-        - [ ] ...
-        - [ ] ...
-    validations:
-      required: true
-
-  - type: textarea
-    id: additional-context
-    attributes:
-      label: Additional context
-      description: Links to related PRs, docs, issues in other repositories, roadmap items, or implementation notes.

.github/workflows/golang-test-darwin.yml

@@ -43,5 +43,13 @@ jobs:
         run: git --no-pager diff --exit-code
 
       - name: Test
-        run: NETBIRD_STORE_ENGINE=${{ matrix.store }} CI=true go test -tags=devcert -exec 'sudo --preserve-env=CI,NETBIRD_STORE_ENGINE' -timeout 5m -p 1 $(go list ./... | grep -v -e /management -e /signal -e /relay -e /proxy -e /combined)
+        # Exclude client/ui-wails: its main.go uses //go:embed all:frontend/dist,
+        # which fails to compile until the frontend has been built. The Wails UI
+        # has no Go-side unit tests, and its release pipeline runs `pnpm build`
+        # before goreleaser.
+        # `go list -e` lets the listing succeed even though the embed fails to
+        # resolve; the grep then drops the broken package by path. Without -e,
+        # go list aborts with empty stdout and `go test` falls back to the repo
+        # root, which has no Go files.
+        run: NETBIRD_STORE_ENGINE=${{ matrix.store }} CI=true go test -tags=devcert -exec 'sudo --preserve-env=CI,NETBIRD_STORE_ENGINE' -timeout 5m -p 1 $(go list -e ./... | grep -v -e /management -e /signal -e /relay -e /proxy -e /combined -e /client/ui-wails)
 

.github/workflows/golang-test-linux.yml

@@ -154,7 +154,15 @@ jobs:
         run: git --no-pager diff --exit-code
 
       - name: Test
-        run: CGO_ENABLED=1 GOARCH=${{ matrix.arch }} CI=true go test -tags devcert -exec 'sudo' -timeout 10m -p 1 $(go list ./... | grep -v -e /management -e /signal -e /relay -e /proxy -e /combined)
+        # Exclude client/ui-wails: its main.go uses //go:embed all:frontend/dist,
+        # which fails to compile until the frontend has been built. The Wails UI
+        # has no Go-side unit tests, and its release pipeline runs `pnpm build`
+        # before goreleaser.
+        # `go list -e` lets the listing succeed even though the embed fails to
+        # resolve; the grep then drops the broken package by path. Without -e,
+        # go list aborts with empty stdout and `go test` falls back to the repo
+        # root, which has no Go files.
+        run: CGO_ENABLED=1 GOARCH=${{ matrix.arch }} CI=true go test -tags devcert -exec 'sudo' -timeout 10m -p 1 $(go list -e ./... | grep -v -e /management -e /signal -e /relay -e /proxy -e /combined -e /client/ui-wails)
 
   test_client_on_docker:
     name: "Client (Docker) / Unit"
@@ -214,7 +222,7 @@ jobs:
             sh -c ' \
               apk update; apk add --no-cache \
                 ca-certificates iptables ip6tables dbus dbus-dev libpcap-dev build-base; \
-              go test -buildvcs=false -tags devcert -v -timeout 10m -p 1 $(go list -buildvcs=false ./... | grep -v -e /management -e /signal -e /relay -e /proxy -e /combined -e /client/ui -e /upload-server)
+              go test -buildvcs=false -tags devcert -v -timeout 10m -p 1 $(go list -e -buildvcs=false ./... | grep -v -e /management -e /signal -e /relay -e /proxy -e /combined -e /client/ui -e /upload-server)
             '
 
   test_relay:

.github/workflows/golang-test-windows.yml

@@ -64,8 +64,15 @@ jobs:
       - run: PsExec64 -s -w ${{ github.workspace }} C:\hostedtoolcache\windows\go\${{ steps.go.outputs.go-version }}\x64\bin\go.exe env -w GOCACHE=${{ env.modcache }}
       - run: PsExec64 -s -w ${{ github.workspace }} C:\hostedtoolcache\windows\go\${{ steps.go.outputs.go-version }}\x64\bin\go.exe mod tidy
       - name: Generate test script
+        # Exclude client/ui-wails: its main.go uses //go:embed all:frontend/dist,
+        # which fails to compile until the frontend has been built. The Wails UI
+        # has no Go-side unit tests, and its release pipeline runs `pnpm build`
+        # before goreleaser.
+        # `go list -e` lets the listing succeed even though the embed fails to
+        # resolve; the Where-Object pipeline then drops the broken package by
+        # path. Without -e, go list aborts with empty stdout.
         run: |
-          $packages = go list ./... | Where-Object { $_ -notmatch '/management' } | Where-Object { $_ -notmatch '/relay' } | Where-Object { $_ -notmatch '/signal' } | Where-Object { $_ -notmatch '/proxy' } | Where-Object { $_ -notmatch '/combined' }
+          $packages = go list -e ./... | Where-Object { $_ -notmatch '/management' } | Where-Object { $_ -notmatch '/relay' } | Where-Object { $_ -notmatch '/signal' } | Where-Object { $_ -notmatch '/proxy' } | Where-Object { $_ -notmatch '/combined' } | Where-Object { $_ -notmatch '/client/ui-wails' }
           $goExe = "C:\hostedtoolcache\windows\go\${{ steps.go.outputs.go-version }}\x64\bin\go.exe"
           $cmd = "$goExe test -tags=devcert -timeout 10m -p 1 $($packages -join ' ') > test-out.txt 2>&1"
           Set-Content -Path "${{ github.workspace }}\run-tests.cmd" -Value $cmd

.github/workflows/golangci-lint.yml

@@ -20,7 +20,7 @@ jobs:
         uses: codespell-project/actions-codespell@v2
         with:
           ignore_words_list: erro,clienta,hastable,iif,groupd,testin,groupe,cros,ans,deriver,te,userA
-          skip: go.mod,go.sum,**/proxy/web/**
+          skip: go.mod,go.sum,**/proxy/web/**,**/pnpm-lock.yaml,**/package-lock.json
   golangci:
     strategy:
       fail-fast: false
@@ -51,6 +51,15 @@ jobs:
       - name: Install dependencies
         if: matrix.os == 'ubuntu-latest'
         run: sudo apt update && sudo apt install -y -q libgtk-3-dev libayatana-appindicator3-dev libgl1-mesa-dev xorg-dev libpcap-dev
+      - name: Stub Wails frontend bundle
+        # client/ui-wails/main.go has //go:embed all:frontend/dist. The
+        # directory is produced by `pnpm run build` and is gitignored, so
+        # lint-only runs (no frontend toolchain) need a placeholder file
+        # for the embed pattern to match.
+        shell: bash
+        run: |
+          mkdir -p client/ui-wails/frontend/dist
+          touch client/ui-wails/frontend/dist/.embed-placeholder
       - name: golangci-lint
         uses: golangci/golangci-lint-action@4afd733a84b1f43292c63897423277bb7f4313a9 # v8.0.0
         with:

.github/workflows/release.yml

@@ -349,8 +349,18 @@ jobs:
       - name: check git status
         run: git --no-pager diff --exit-code
 
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Set up pnpm
+        uses: pnpm/action-setup@v3
+        with:
+          version: 9
+
       - name: Install dependencies
-        run: sudo apt update && sudo apt install -y -q libappindicator3-dev gir1.2-appindicator3-0.1 libxxf86vm-dev gcc-mingw-w64-x86-64
+        run: sudo apt update && sudo apt install -y -q libgtk-3-dev libwebkit2gtk-4.1-dev libsoup-3.0-dev libayatana-appindicator3-dev gcc-mingw-w64-x86-64
 
       - name: Decode GPG signing key
         if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
@@ -370,9 +380,9 @@ jobs:
       - name: Install goversioninfo
         run: go install github.com/josephspurrier/goversioninfo/cmd/goversioninfo@233067e
       - name: Generate windows syso amd64
-        run: goversioninfo -64 -icon client/ui/assets/netbird.ico -manifest client/ui/manifest.xml -product-name ${{ env.PRODUCT_NAME }}-"UI" -copyright "${{ env.COPYRIGHT }}" -ver-major ${{ steps.semver_parser.outputs.major }} -ver-minor ${{ steps.semver_parser.outputs.minor }} -ver-patch ${{ steps.semver_parser.outputs.patch }} -ver-build 0 -file-version ${{ steps.semver_parser.outputs.fullversion }}.0 -product-version ${{ steps.semver_parser.outputs.fullversion }}.0 -o client/ui/resources_windows_amd64.syso
+        run: goversioninfo -64 -icon client/ui-wails/build/windows/icon.ico -manifest client/ui-wails/build/windows/wails.exe.manifest -product-name ${{ env.PRODUCT_NAME }}-"UI" -copyright "${{ env.COPYRIGHT }}" -ver-major ${{ steps.semver_parser.outputs.major }} -ver-minor ${{ steps.semver_parser.outputs.minor }} -ver-patch ${{ steps.semver_parser.outputs.patch }} -ver-build 0 -file-version ${{ steps.semver_parser.outputs.fullversion }}.0 -product-version ${{ steps.semver_parser.outputs.fullversion }}.0 -o client/ui-wails/resources_windows_amd64.syso
       - name: Generate windows syso arm64
-        run: goversioninfo -arm -64 -icon client/ui/assets/netbird.ico -manifest client/ui/manifest.xml -product-name ${{ env.PRODUCT_NAME }}-"UI" -copyright "${{ env.COPYRIGHT }}" -ver-major ${{ steps.semver_parser.outputs.major }} -ver-minor ${{ steps.semver_parser.outputs.minor }} -ver-patch ${{ steps.semver_parser.outputs.patch }} -ver-build 0 -file-version ${{ steps.semver_parser.outputs.fullversion }}.0 -product-version ${{ steps.semver_parser.outputs.fullversion }}.0 -o client/ui/resources_windows_arm64.syso
+        run: goversioninfo -arm -64 -icon client/ui-wails/build/windows/icon.ico -manifest client/ui-wails/build/windows/wails.exe.manifest -product-name ${{ env.PRODUCT_NAME }}-"UI" -copyright "${{ env.COPYRIGHT }}" -ver-major ${{ steps.semver_parser.outputs.major }} -ver-minor ${{ steps.semver_parser.outputs.minor }} -ver-patch ${{ steps.semver_parser.outputs.patch }} -ver-build 0 -file-version ${{ steps.semver_parser.outputs.fullversion }}.0 -product-version ${{ steps.semver_parser.outputs.fullversion }}.0 -o client/ui-wails/resources_windows_arm64.syso
 
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v4
@@ -439,6 +449,14 @@ jobs:
         run: go mod tidy
       - name: check git status
         run: git --no-pager diff --exit-code
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+      - name: Set up pnpm
+        uses: pnpm/action-setup@v3
+        with:
+          version: 9
       - name: Run GoReleaser
         id: goreleaser
         uses: goreleaser/goreleaser-action@v4

.gitignore

@@ -33,4 +33,3 @@ infrastructure_files/setup-*.env
 vendor/
 /netbird
 client/netbird-electron/
-management/server/types/testdata/

.golangci.yaml

@@ -114,6 +114,16 @@ linters:
       - linters:
           - staticcheck
         text: "QF1012"
+      # client/ui-wails/main.go uses //go:embed all:frontend/dist; the
+      # directory is populated by `pnpm build` in the release pipeline
+      # and missing at lint time, so the embed parses to "no matching
+      # files found" — surfaced by golangci-lint's typecheck pre-pass.
+      # Suppress just that one diagnostic; the rest of the package
+      # (services/, tray.go, grpc.go, ...) still gets linted normally.
+      - linters:
+          - typecheck
+        path: client/ui-wails/main\.go
+        text: "pattern all:frontend/dist"
     paths:
       - third_party$
       - builtin$

.goreleaser_ui.yaml

@@ -1,9 +1,14 @@
 version: 2
 
 project_name: netbird-ui
+
+before:
+  hooks:
+    - sh -c 'cd client/ui-wails/frontend && pnpm install --frozen-lockfile && pnpm build'
+
 builds:
   - id: netbird-ui
-    dir: client/ui
+    dir: client/ui-wails
     binary: netbird-ui
     env:
       - CGO_ENABLED=1
@@ -16,7 +21,7 @@ builds:
     mod_timestamp: "{{ .CommitTimestamp }}"
 
   - id: netbird-ui-windows-amd64
-    dir: client/ui
+    dir: client/ui-wails
     binary: netbird-ui
     env:
       - CGO_ENABLED=1
@@ -31,7 +36,7 @@ builds:
     mod_timestamp: "{{ .CommitTimestamp }}"
 
   - id: netbird-ui-windows-arm64
-    dir: client/ui
+    dir: client/ui-wails
     binary: netbird-ui
     env:
       - CGO_ENABLED=1
@@ -70,12 +75,15 @@ nfpms:
     scripts:
       postinstall: "release_files/ui-post-install.sh"
     contents:
-      - src: client/ui/build/netbird.desktop
+      - src: client/ui-wails/build/linux/netbird.desktop
         dst: /usr/share/applications/netbird.desktop
-      - src: client/ui/assets/netbird.png
+      - src: client/ui-wails/build/appicon.png
         dst: /usr/share/pixmaps/netbird.png
     dependencies:
       - netbird
+      - libgtk-3-0
+      - libwebkit2gtk-4.1-0
+      - libayatana-appindicator3-1
 
   - maintainer: Netbird <dev@netbird.io>
     description: Netbird client UI.
@@ -89,12 +97,15 @@ nfpms:
     scripts:
       postinstall: "release_files/ui-post-install.sh"
     contents:
-      - src: client/ui/build/netbird.desktop
+      - src: client/ui-wails/build/linux/netbird.desktop
         dst: /usr/share/applications/netbird.desktop
-      - src: client/ui/assets/netbird.png
+      - src: client/ui-wails/build/appicon.png
         dst: /usr/share/pixmaps/netbird.png
     dependencies:
       - netbird
+      - gtk3
+      - webkit2gtk4.1
+      - libayatana-appindicator-gtk3
     rpm:
       signature:
         key_file: '{{ if index .Env "GPG_RPM_KEY_FILE" }}{{ .Env.GPG_RPM_KEY_FILE }}{{ end }}'

.goreleaser_ui_darwin.yaml

@@ -1,9 +1,14 @@
 version: 2
 
 project_name: netbird-ui
+
+before:
+  hooks:
+    - sh -c 'cd client/ui-wails/frontend && pnpm install --frozen-lockfile && pnpm build'
+
 builds:
   - id: netbird-ui-darwin
-    dir: client/ui
+    dir: client/ui-wails
     binary: netbird-ui
     env:
       - CGO_ENABLED=1
@@ -20,8 +25,6 @@ builds:
     ldflags:
       - -s -w -X github.com/netbirdio/netbird/version.version={{.Version}} -X main.commit={{.Commit}} -X main.date={{.CommitDate}} -X main.builtBy=goreleaser
     mod_timestamp: "{{ .CommitTimestamp }}"
-    tags:
-      - load_wgnt_from_rsrc
 
 universal_binaries:
   - id: netbird-ui-darwin

client/android/client.go

@@ -301,11 +301,10 @@ func (c *Client) PeersList() *PeerInfoArray {
 	peerInfos := make([]PeerInfo, len(fullStatus.Peers))
 	for n, p := range fullStatus.Peers {
 		pi := PeerInfo{
-			IP:         p.IP,
-			IPv6:       p.IPv6,
-			FQDN:       p.FQDN,
-			ConnStatus: int(p.ConnStatus),
-			Routes:     PeerRoutes{routes: maps.Keys(p.GetRoutes())},
+			p.IP,
+			p.FQDN,
+			int(p.ConnStatus),
+			PeerRoutes{routes: maps.Keys(p.GetRoutes())},
 		}
 		peerInfos[n] = pi
 	}
@@ -337,84 +336,43 @@ func (c *Client) Networks() *NetworkArray {
 		return nil
 	}
 
-	routesMap := routeManager.GetClientRoutesWithNetID()
-	v6Merged := route.V6ExitMergeSet(routesMap)
-	resolvedDomains := c.recorder.GetResolvedDomainsStates()
-
 	networkArray := &NetworkArray{
 		items: make([]Network, 0),
 	}
 
-	for id, routes := range routesMap {
+	resolvedDomains := c.recorder.GetResolvedDomainsStates()
+
+	for id, routes := range routeManager.GetClientRoutesWithNetID() {
 		if len(routes) == 0 {
 			continue
 		}
-		if _, skip := v6Merged[id]; skip {
-			continue
+
+		r := routes[0]
+		domains := c.getNetworkDomainsFromRoute(r, resolvedDomains)
+		netStr := r.Network.String()
+
+		if r.IsDynamic() {
+			netStr = r.Domains.SafeString()
 		}
 
-		network := c.buildNetwork(id, routes, routeSelector.IsSelected(id), resolvedDomains, v6Merged)
-		if network == nil {
+		routePeer, err := c.recorder.GetPeer(routes[0].Peer)
+		if err != nil {
+			log.Errorf("could not get peer info for %s: %v", routes[0].Peer, err)
 			continue
 		}
-		networkArray.Add(*network)
+		network := Network{
+			Name:       string(id),
+			Network:    netStr,
+			Peer:       routePeer.FQDN,
+			Status:     routePeer.ConnStatus.String(),
+			IsSelected: routeSelector.IsSelected(id),
+			Domains:    domains,
+		}
+		networkArray.Add(network)
 	}
 	return networkArray
 }
 
-func (c *Client) buildNetwork(id route.NetID, routes []*route.Route, selected bool, resolvedDomains map[domain.Domain]peer.ResolvedDomainInfo, v6Merged map[route.NetID]struct{}) *Network {
-	r := routes[0]
-	netStr := r.Network.String()
-	if r.IsDynamic() {
-		netStr = r.Domains.SafeString()
-	}
-
-	routePeer, err := c.findBestRoutePeer(routes)
-	if err != nil {
-		log.Errorf("could not get peer info for route %s: %v", id, err)
-		return nil
-	}
-
-	network := &Network{
-		Name:       string(id),
-		Network:    netStr,
-		Peer:       routePeer.FQDN,
-		Status:     routePeer.ConnStatus.String(),
-		IsSelected: selected,
-		Domains:    c.getNetworkDomainsFromRoute(r, resolvedDomains),
-	}
-
-	if route.IsV4DefaultRoute(r.Network) && route.HasV6ExitPair(id, v6Merged) {
-		network.Network = "0.0.0.0/0, ::/0"
-	}
-
-	return network
-}
-
-// findBestRoutePeer returns the peer actively routing traffic for the given
-// HA route group. Falls back to the first connected peer, then the first peer.
-func (c *Client) findBestRoutePeer(routes []*route.Route) (peer.State, error) {
-	netStr := routes[0].Network.String()
-
-	fullStatus := c.recorder.GetFullStatus()
-	for _, p := range fullStatus.Peers {
-		if _, ok := p.GetRoutes()[netStr]; ok {
-			return p, nil
-		}
-	}
-
-	for _, r := range routes {
-		p, err := c.recorder.GetPeer(r.Peer)
-		if err != nil {
-			continue
-		}
-		if p.ConnStatus == peer.StatusConnected {
-			return p, nil
-		}
-	}
-	return c.recorder.GetPeer(routes[0].Peer)
-}
-
 // OnUpdatedHostDNS update the DNS servers addresses for root zones
 func (c *Client) OnUpdatedHostDNS(list *DNSList) error {
 	dnsServer, err := dns.GetServerDns()

client/android/peer_notifier.go

@@ -14,7 +14,6 @@ const (
 // PeerInfo describe information about the peers. It designed for the UI usage
 type PeerInfo struct {
 	IP         string
-	IPv6       string
 	FQDN       string
 	ConnStatus int
 	Routes     PeerRoutes

client/android/preferences.go

@@ -307,24 +307,6 @@ func (p *Preferences) SetBlockInbound(block bool) {
 	p.configInput.BlockInbound = &block
 }
 
-// GetDisableIPv6 reads disable IPv6 setting from config file
-func (p *Preferences) GetDisableIPv6() (bool, error) {
-	if p.configInput.DisableIPv6 != nil {
-		return *p.configInput.DisableIPv6, nil
-	}
-
-	cfg, err := profilemanager.ReadConfig(p.configInput.ConfigPath)
-	if err != nil {
-		return false, err
-	}
-	return cfg.DisableIPv6, err
-}
-
-// SetDisableIPv6 stores the given value and waits for commit
-func (p *Preferences) SetDisableIPv6(disable bool) {
-	p.configInput.DisableIPv6 = &disable
-}
-
 // Commit writes out the changes to the config file
 func (p *Preferences) Commit() error {
 	_, err := profilemanager.UpdateOrCreateConfig(p.configInput)

client/android/route_command.go

@@ -18,12 +18,9 @@ func executeRouteToggle(id string, manager routemanager.Manager,
 	netID := route.NetID(id)
 	routes := []route.NetID{netID}
 
-	routesMap := manager.GetClientRoutesWithNetID()
-	routes = route.ExpandV6ExitPairs(routes, routesMap)
+	log.Debugf("%s with id: %s", operationName, id)
 
-	log.Debugf("%s with ids: %v", operationName, routes)
-
-	if err := routeOperation(routes, maps.Keys(routesMap)); err != nil {
+	if err := routeOperation(routes, maps.Keys(manager.GetClientRoutesWithNetID())); err != nil {
 		log.Debugf("error when %s: %s", operationName, err)
 		return fmt.Errorf("error %s: %w", operationName, err)
 	}

client/anonymize/anonymize.go

@@ -9,7 +9,6 @@ import (
 	"net/url"
 	"regexp"
 	"slices"
-	"strconv"
 	"strings"
 )
 
@@ -27,9 +26,8 @@ type Anonymizer struct {
 }
 
 func DefaultAddresses() (netip.Addr, netip.Addr) {
-	// 198.51.100.0 (RFC 5737 TEST-NET-2), 2001:db8:ffff:: (RFC 3849 documentation, last /48)
-	// The old start 100:: (discard, RFC 6666) is now used for fake IPs on Android.
-	return netip.AddrFrom4([4]byte{198, 51, 100, 0}), netip.MustParseAddr("2001:db8:ffff::")
+	// 198.51.100.0, 100::
+	return netip.AddrFrom4([4]byte{198, 51, 100, 0}), netip.AddrFrom16([16]byte{0x01})
 }
 
 func NewAnonymizer(startIPv4, startIPv6 netip.Addr) *Anonymizer {
@@ -50,7 +48,7 @@ func (a *Anonymizer) AnonymizeIP(ip netip.Addr) netip.Addr {
 		ip.IsLinkLocalUnicast() ||
 		ip.IsLinkLocalMulticast() ||
 		ip.IsInterfaceLocalMulticast() ||
-		(ip.Is4() && ip.IsPrivate()) ||
+		ip.IsPrivate() ||
 		ip.IsUnspecified() ||
 		ip.IsMulticast() ||
 		isWellKnown(ip) ||
@@ -98,11 +96,6 @@ func (a *Anonymizer) isInAnonymizedRange(ip netip.Addr) bool {
 }
 
 func (a *Anonymizer) AnonymizeIPString(ip string) string {
-	// Handle CIDR notation (e.g. "2001:db8::/32")
-	if prefix, err := netip.ParsePrefix(ip); err == nil {
-		return a.AnonymizeIP(prefix.Addr()).String() + "/" + strconv.Itoa(prefix.Bits())
-	}
-
 	addr, err := netip.ParseAddr(ip)
 	if err != nil {
 		return ip
@@ -157,7 +150,7 @@ func (a *Anonymizer) AnonymizeURI(uri string) string {
 	if u.Opaque != "" {
 		host, port, err := net.SplitHostPort(u.Opaque)
 		if err == nil {
-			anonymizedHost = net.JoinHostPort(a.AnonymizeDomain(host), port)
+			anonymizedHost = fmt.Sprintf("%s:%s", a.AnonymizeDomain(host), port)
 		} else {
 			anonymizedHost = a.AnonymizeDomain(u.Opaque)
 		}
@@ -165,7 +158,7 @@ func (a *Anonymizer) AnonymizeURI(uri string) string {
 	} else if u.Host != "" {
 		host, port, err := net.SplitHostPort(u.Host)
 		if err == nil {
-			anonymizedHost = net.JoinHostPort(a.AnonymizeDomain(host), port)
+			anonymizedHost = fmt.Sprintf("%s:%s", a.AnonymizeDomain(host), port)
 		} else {
 			anonymizedHost = a.AnonymizeDomain(u.Host)
 		}

client/anonymize/anonymize_test.go

@@ -13,7 +13,7 @@ import (
 
 func TestAnonymizeIP(t *testing.T) {
 	startIPv4 := netip.MustParseAddr("198.51.100.0")
-	startIPv6 := netip.MustParseAddr("2001:db8:ffff::")
+	startIPv6 := netip.MustParseAddr("100::")
 	anonymizer := anonymize.NewAnonymizer(startIPv4, startIPv6)
 
 	tests := []struct {
@@ -26,9 +26,9 @@ func TestAnonymizeIP(t *testing.T) {
 		{"Second Public IPv4", "4.3.2.1", "198.51.100.1"},
 		{"Repeated IPv4", "1.2.3.4", "198.51.100.0"},
 		{"Private IPv4", "192.168.1.1", "192.168.1.1"},
-		{"First Public IPv6", "2607:f8b0:4005:805::200e", "2001:db8:ffff::"},
-		{"Second Public IPv6", "a::b", "2001:db8:ffff::1"},
-		{"Repeated IPv6", "2607:f8b0:4005:805::200e", "2001:db8:ffff::"},
+		{"First Public IPv6", "2607:f8b0:4005:805::200e", "100::"},
+		{"Second Public IPv6", "a::b", "100::1"},
+		{"Repeated IPv6", "2607:f8b0:4005:805::200e", "100::"},
 		{"Private IPv6", "fe80::1", "fe80::1"},
 		{"In Range IPv4", "198.51.100.2", "198.51.100.2"},
 	}
@@ -274,27 +274,17 @@ func TestAnonymizeString_IPAddresses(t *testing.T) {
 		{
 			name:   "IPv6 Address",
 			input:  "Access attempted from 2001:db8::ff00:42",
-			expect: "Access attempted from 2001:db8:ffff::",
+			expect: "Access attempted from 100::",
 		},
 		{
 			name:   "IPv6 Address with Port",
 			input:  "Access attempted from [2001:db8::ff00:42]:8080",
-			expect: "Access attempted from [2001:db8:ffff::]:8080",
+			expect: "Access attempted from [100::]:8080",
 		},
 		{
 			name:   "Both IPv4 and IPv6",
 			input:  "IPv4: 142.108.0.1 and IPv6: 2001:db8::ff00:43",
-			expect: "IPv4: 198.51.100.1 and IPv6: 2001:db8:ffff::1",
-		},
-		{
-			name:   "STUN URI with IPv6",
-			input:  "Connecting to stun:[2001:db8::ff00:42]:3478",
-			expect: "Connecting to stun:[2001:db8:ffff::]:3478",
-		},
-		{
-			name:   "HTTPS URI with IPv6",
-			input:  "Visit https://[2001:db8::ff00:42]:443/path",
-			expect: "Visit https://[2001:db8:ffff::]:443/path",
+			expect: "IPv4: 198.51.100.1 and IPv6: 100::1",
 		},
 	}
 

client/cmd/ssh.go

@@ -523,7 +523,7 @@ func parseHostnameAndCommand(args []string) error {
 }
 
 func runSSH(ctx context.Context, addr string, cmd *cobra.Command) error {
-	target := net.JoinHostPort(strings.Trim(addr, "[]"), strconv.Itoa(port))
+	target := fmt.Sprintf("%s:%d", addr, port)
 	c, err := sshclient.Dial(ctx, target, username, sshclient.DialOptions{
 		KnownHostsFile:     knownHostsFile,
 		IdentityFile:       identityFile,
@@ -787,10 +787,10 @@ func isUnixSocket(path string) bool {
 	return strings.HasPrefix(path, "/") || strings.HasPrefix(path, "./")
 }
 
-// normalizeLocalHost converts "*" to "" for binding to all interfaces (dual-stack).
+// normalizeLocalHost converts "*" to "0.0.0.0" for binding to all interfaces.
 func normalizeLocalHost(host string) string {
 	if host == "*" {
-		return ""
+		return "0.0.0.0"
 	}
 	return host
 }

client/cmd/ssh_test.go

@@ -527,10 +527,10 @@ func TestParsePortForward(t *testing.T) {
 		{
 			name:           "wildcard bind all interfaces",
 			spec:           "*:8080:localhost:80",
-			expectedLocal:  ":8080",
+			expectedLocal:  "0.0.0.0:8080",
 			expectedRemote: "localhost:80",
 			expectError:    false,
-			description:    "Wildcard * should bind to all interfaces (dual-stack)",
+			description:    "Wildcard * should bind to all interfaces (0.0.0.0)",
 		},
 		{
 			name:           "wildcard for port only",

client/cmd/status.go

@@ -20,7 +20,6 @@ import (
 var (
 	detailFlag           bool
 	ipv4Flag             bool
-	ipv6Flag             bool
 	jsonFlag             bool
 	yamlFlag             bool
 	ipsFilter            []string
@@ -46,9 +45,8 @@ func init() {
 	statusCmd.PersistentFlags().BoolVar(&jsonFlag, "json", false, "display detailed status information in json format")
 	statusCmd.PersistentFlags().BoolVar(&yamlFlag, "yaml", false, "display detailed status information in yaml format")
 	statusCmd.PersistentFlags().BoolVar(&ipv4Flag, "ipv4", false, "display only NetBird IPv4 of this peer, e.g., --ipv4 will output 100.64.0.33")
-	statusCmd.PersistentFlags().BoolVar(&ipv6Flag, "ipv6", false, "display only NetBird IPv6 of this peer")
-	statusCmd.MarkFlagsMutuallyExclusive("detail", "json", "yaml", "ipv4", "ipv6")
-	statusCmd.PersistentFlags().StringSliceVar(&ipsFilter, "filter-by-ips", []string{}, "filters the detailed output by a list of one or more IPs (v4 or v6), e.g., --filter-by-ips 100.64.0.100,fd00::1")
+	statusCmd.MarkFlagsMutuallyExclusive("detail", "json", "yaml", "ipv4")
+	statusCmd.PersistentFlags().StringSliceVar(&ipsFilter, "filter-by-ips", []string{}, "filters the detailed output by a list of one or more IPs, e.g., --filter-by-ips 100.64.0.100,100.64.0.200")
 	statusCmd.PersistentFlags().StringSliceVar(&prefixNamesFilter, "filter-by-names", []string{}, "filters the detailed output by a list of one or more peer FQDN or hostnames, e.g., --filter-by-names peer-a,peer-b.netbird.cloud")
 	statusCmd.PersistentFlags().StringVar(&statusFilter, "filter-by-status", "", "filters the detailed output by connection status(idle|connecting|connected), e.g., --filter-by-status connected")
 	statusCmd.PersistentFlags().StringVar(&connectionTypeFilter, "filter-by-connection-type", "", "filters the detailed output by connection type (P2P|Relayed), e.g., --filter-by-connection-type P2P")
@@ -103,14 +101,6 @@ func statusFunc(cmd *cobra.Command, args []string) error {
 		return nil
 	}
 
-	if ipv6Flag {
-		ipv6 := resp.GetFullStatus().GetLocalPeerState().GetIpv6()
-		if ipv6 != "" {
-			cmd.Print(parseInterfaceIP(ipv6))
-		}
-		return nil
-	}
-
 	pm := profilemanager.NewProfileManager()
 	var profName string
 	if activeProf, err := pm.GetActiveProfile(); err == nil {

client/cmd/system.go

@@ -8,7 +8,6 @@ const (
 	disableFirewallFlag     = "disable-firewall"
 	blockLANAccessFlag      = "block-lan-access"
 	blockInboundFlag        = "block-inbound"
-	disableIPv6Flag         = "disable-ipv6"
 )
 
 var (
@@ -18,7 +17,6 @@ var (
 	disableFirewall     bool
 	blockLANAccess      bool
 	blockInbound        bool
-	disableIPv6         bool
 )
 
 func init() {
@@ -41,7 +39,4 @@ func init() {
 	upCmd.PersistentFlags().BoolVar(&blockInbound, blockInboundFlag, false,
 		"Block inbound connections. If enabled, the client will not allow any inbound connections to the local machine nor routed networks.\n"+
 			"This overrides any policies received from the management service.")
-
-	upCmd.PersistentFlags().BoolVar(&disableIPv6, disableIPv6Flag, false,
-		"Disable IPv6 overlay. If enabled, the client won't request or use an IPv6 overlay address.")
 }

client/cmd/up.go

@@ -435,10 +435,6 @@ func setupSetConfigReq(customDNSAddressConverted []byte, cmd *cobra.Command, pro
 		req.BlockInbound = &blockInbound
 	}
 
-	if cmd.Flag(disableIPv6Flag).Changed {
-		req.DisableIpv6 = &disableIPv6
-	}
-
 	if cmd.Flag(enableLazyConnectionFlag).Changed {
 		req.LazyConnectionEnabled = &lazyConnEnabled
 	}
@@ -556,10 +552,6 @@ func setupConfig(customDNSAddressConverted []byte, cmd *cobra.Command, configFil
 		ic.BlockInbound = &blockInbound
 	}
 
-	if cmd.Flag(disableIPv6Flag).Changed {
-		ic.DisableIPv6 = &disableIPv6
-	}
-
 	if cmd.Flag(enableLazyConnectionFlag).Changed {
 		ic.LazyConnectionEnabled = &lazyConnEnabled
 	}
@@ -674,10 +666,6 @@ func setupLoginRequest(providedSetupKey string, customDNSAddressConverted []byte
 		loginRequest.BlockInbound = &blockInbound
 	}
 
-	if cmd.Flag(disableIPv6Flag).Changed {
-		loginRequest.DisableIpv6 = &disableIPv6
-	}
-
 	if cmd.Flag(enableLazyConnectionFlag).Changed {
 		loginRequest.LazyConnectionEnabled = &lazyConnEnabled
 	}

client/embed/embed.go

@@ -12,7 +12,6 @@ import (
 	"sync"
 
 	"github.com/sirupsen/logrus"
-	wgdevice "golang.zx2c4.com/wireguard/device"
 	wgnetstack "golang.zx2c4.com/wireguard/tun/netstack"
 
 	"github.com/netbirdio/netbird/client/iface"
@@ -81,8 +80,6 @@ type Options struct {
 	StatePath string
 	// DisableClientRoutes disables the client routes
 	DisableClientRoutes bool
-	// DisableIPv6 disables IPv6 overlay addressing
-	DisableIPv6 bool
 	// BlockInbound blocks all inbound connections from peers
 	BlockInbound bool
 	// WireguardPort is the port for the tunnel interface. Use 0 for a random port.
@@ -174,7 +171,6 @@ func New(opts Options) (*Client, error) {
 		PreSharedKey:        &opts.PreSharedKey,
 		DisableServerRoutes: &t,
 		DisableClientRoutes: &opts.DisableClientRoutes,
-		DisableIPv6:         &opts.DisableIPv6,
 		BlockInbound:        &opts.BlockInbound,
 		WireguardPort:       opts.WireguardPort,
 		MTU:                 opts.MTU,
@@ -474,55 +470,6 @@ func (c *Client) VerifySSHHostKey(peerAddress string, key []byte) error {
 	return sshcommon.VerifyHostKey(storedKey, key, peerAddress)
 }
 
-// WGTuning bundles runtime-adjustable WireGuard knobs exposed by the embed
-// client. Nil fields are left unchanged; set a non-nil pointer to apply.
-type WGTuning struct {
-	// PreallocatedBuffersPerPool caps each per-Device WaitPool.
-	// Zero means "unbounded" (no cap). Live-tunable only if the underlying
-	// Device was originally created with a nonzero cap.
-	PreallocatedBuffersPerPool *uint32
-}
-
-// SetWGTuning applies the given tuning to this client's live Device.
-// Startup-only knobs (batch size) must be set via the package-level
-// setters before Start.
-func (c *Client) SetWGTuning(t WGTuning) error {
-	engine, err := c.getEngine()
-	if err != nil {
-		return err
-	}
-	return engine.SetWGTuning(internal.WGTuning{
-		PreallocatedBuffersPerPool: t.PreallocatedBuffersPerPool,
-	})
-}
-
-// SetWGDefaultPreallocatedBuffersPerPool sets the default WaitPool cap
-// applied to Devices created after this call. Zero disables the cap.
-// Existing Devices are unaffected; use Client.SetWGTuning for that.
-func SetWGDefaultPreallocatedBuffersPerPool(n uint32) {
-	wgdevice.SetPreallocatedBuffersPerPool(n)
-}
-
-// WGDefaultPreallocatedBuffersPerPool returns the current default WaitPool
-// cap applied to newly-created Devices.
-func WGDefaultPreallocatedBuffersPerPool() uint32 {
-	return wgdevice.PreallocatedBuffersPerPool
-}
-
-// SetWGDefaultMaxBatchSize sets the default per-Device batch size applied
-// to Devices created after this call. Zero means "use the bind+tun default"
-// (NOT unlimited). Must be called before Start to take effect for a new
-// Client.
-func SetWGDefaultMaxBatchSize(n uint32) {
-	wgdevice.SetMaxBatchSizeOverride(n)
-}
-
-// WGDefaultMaxBatchSize returns the current default batch-size override.
-// Zero means "no override".
-func WGDefaultMaxBatchSize() uint32 {
-	return wgdevice.MaxBatchSizeOverride
-}
-
 // StartCapture begins capturing packets on this client's tunnel device.
 // Only one capture can be active at a time; starting a new one stops the previous.
 // Call StopCapture (or CaptureSession.Stop) to end it.

client/firewall/iptables/acl_linux.go

@@ -40,7 +40,6 @@ type aclManager struct {
 	entries         aclEntries
 	optionalEntries map[string][]entry
 	ipsetStore      *ipsetStore
-	v6              bool
 
 	stateManager *statemanager.Manager
 }
@@ -52,7 +51,6 @@ func newAclManager(iptablesClient *iptables.IPTables, wgIface iFaceMapper) (*acl
 		entries:         make(map[string][][]string),
 		optionalEntries: make(map[string][]entry),
 		ipsetStore:      newIpsetStore(),
-		v6:              iptablesClient.Proto() == iptables.ProtocolIPv6,
 	}, nil
 }
 
@@ -87,11 +85,7 @@ func (m *aclManager) AddPeerFiltering(
 	chain := chainNameInputRules
 
 	ipsetName = transformIPsetName(ipsetName, sPort, dPort, action)
-	if m.v6 && ipsetName != "" {
-		ipsetName += "-v6"
-	}
-	proto := protoForFamily(protocol, m.v6)
-	specs := filterRuleSpecs(ip, proto, sPort, dPort, action, ipsetName)
+	specs := filterRuleSpecs(ip, string(protocol), sPort, dPort, action, ipsetName)
 
 	mangleSpecs := slices.Clone(specs)
 	mangleSpecs = append(mangleSpecs,
@@ -115,7 +109,6 @@ func (m *aclManager) AddPeerFiltering(
 				ip:        ip.String(),
 				chain:     chain,
 				specs:     specs,
-				v6:        m.v6,
 			}}, nil
 		}
 
@@ -168,7 +161,6 @@ func (m *aclManager) AddPeerFiltering(
 		ipsetName:   ipsetName,
 		ip:          ip.String(),
 		chain:       chain,
-		v6:          m.v6,
 	}
 
 	m.updateState()
@@ -421,13 +413,8 @@ func (m *aclManager) updateState() {
 	currentState.Lock()
 	defer currentState.Unlock()
 
-	if m.v6 {
-		currentState.ACLEntries6 = m.entries
-		currentState.ACLIPsetStore6 = m.ipsetStore
-	} else {
-		currentState.ACLEntries = m.entries
-		currentState.ACLIPsetStore = m.ipsetStore
-	}
+	currentState.ACLEntries = m.entries
+	currentState.ACLIPsetStore = m.ipsetStore
 
 	if err := m.stateManager.UpdateState(currentState); err != nil {
 		log.Errorf("failed to update state: %v", err)
@@ -435,22 +422,13 @@ func (m *aclManager) updateState() {
 }
 
 // filterRuleSpecs returns the specs of a filtering rule
-// protoForFamily translates ICMP to ICMPv6 for ip6tables.
-// ip6tables requires "ipv6-icmp" (or "icmpv6") instead of "icmp".
-func protoForFamily(protocol firewall.Protocol, v6 bool) string {
-	if v6 && protocol == firewall.ProtocolICMP {
-		return "ipv6-icmp"
-	}
-	return string(protocol)
-}
-
 func filterRuleSpecs(ip net.IP, protocol string, sPort, dPort *firewall.Port, action firewall.Action, ipsetName string) (specs []string) {
 	// don't use IP matching if IP is 0.0.0.0
 	matchByIP := !ip.IsUnspecified()
 
 	if matchByIP {
 		if ipsetName != "" {
-			specs = append(specs, "-m", "set", "--match-set", ipsetName, "src")
+			specs = append(specs, "-m", "set", "--set", ipsetName, "src")
 		} else {
 			specs = append(specs, "-s", ip.String())
 		}
@@ -496,9 +474,6 @@ func (m *aclManager) createIPSet(name string) error {
 	opts := ipset.CreateOptions{
 		Replace: true,
 	}
-	if m.v6 {
-		opts.Family = ipset.FamilyIPV6
-	}
 
 	if err := ipset.Create(name, ipset.TypeHashNet, opts); err != nil {
 		return fmt.Errorf("create ipset %s: %w", name, err)

client/firewall/iptables/manager_linux.go

@@ -18,10 +18,6 @@ import (
 	"github.com/netbirdio/netbird/client/internal/statemanager"
 )
 
-type resetter interface {
-	Reset() error
-}
-
 // Manager of iptables firewall
 type Manager struct {
 	mutex sync.Mutex
@@ -32,11 +28,6 @@ type Manager struct {
 	aclMgr       *aclManager
 	router       *router
 	rawSupported bool
-
-	// IPv6 counterparts, nil when no v6 overlay
-	ipv6Client *iptables.IPTables
-	aclMgr6    *aclManager
-	router6    *router
 }
 
 // iFaceMapper defines subset methods of interface required for manager
@@ -67,43 +58,9 @@ func Create(wgIface iFaceMapper, mtu uint16) (*Manager, error) {
 		return nil, fmt.Errorf("create acl manager: %w", err)
 	}
 
-	if wgIface.Address().HasIPv6() {
-		if err := m.createIPv6Components(wgIface, mtu); err != nil {
-			return nil, fmt.Errorf("create IPv6 firewall: %w", err)
-		}
-	}
-
 	return m, nil
 }
 
-func (m *Manager) createIPv6Components(wgIface iFaceMapper, mtu uint16) error {
-	ip6Client, err := iptables.NewWithProtocol(iptables.ProtocolIPv6)
-	if err != nil {
-		return fmt.Errorf("init ip6tables: %w", err)
-	}
-	m.ipv6Client = ip6Client
-
-	m.router6, err = newRouter(ip6Client, wgIface, mtu)
-	if err != nil {
-		return fmt.Errorf("create v6 router: %w", err)
-	}
-
-	// Share the same IP forwarding state with the v4 router, since
-	// EnableIPForwarding controls both v4 and v6 sysctls.
-	m.router6.ipFwdState = m.router.ipFwdState
-
-	m.aclMgr6, err = newAclManager(ip6Client, wgIface)
-	if err != nil {
-		return fmt.Errorf("create v6 acl manager: %w", err)
-	}
-
-	return nil
-}
-
-func (m *Manager) hasIPv6() bool {
-	return m.ipv6Client != nil
-}
-
 func (m *Manager) Init(stateManager *statemanager.Manager) error {
 	state := &ShutdownState{
 		InterfaceState: &InterfaceState{
@@ -117,8 +74,13 @@ func (m *Manager) Init(stateManager *statemanager.Manager) error {
 		log.Errorf("failed to update state: %v", err)
 	}
 
-	if err := m.initChains(stateManager); err != nil {
-		return err
+	if err := m.router.init(stateManager); err != nil {
+		return fmt.Errorf("router init: %w", err)
+	}
+
+	if err := m.aclMgr.init(stateManager); err != nil {
+		// TODO: cleanup router
+		return fmt.Errorf("acl manager init: %w", err)
 	}
 
 	if err := m.initNoTrackChain(); err != nil {
@@ -141,41 +103,6 @@ func (m *Manager) Init(stateManager *statemanager.Manager) error {
 	return nil
 }
 
-// initChains initializes router and ACL chains for both address families,
-// rolling back on failure.
-func (m *Manager) initChains(stateManager *statemanager.Manager) error {
-	type initStep struct {
-		name string
-		init func(*statemanager.Manager) error
-		mgr  resetter
-	}
-
-	steps := []initStep{
-		{"router", m.router.init, m.router},
-		{"acl manager", m.aclMgr.init, m.aclMgr},
-	}
-	if m.hasIPv6() {
-		steps = append(steps,
-			initStep{"v6 router", m.router6.init, m.router6},
-			initStep{"v6 acl manager", m.aclMgr6.init, m.aclMgr6},
-		)
-	}
-
-	var initialized []initStep
-	for _, s := range steps {
-		if err := s.init(stateManager); err != nil {
-			for i := len(initialized) - 1; i >= 0; i-- {
-				if rerr := initialized[i].mgr.Reset(); rerr != nil {
-					log.Warnf("rollback %s: %v", initialized[i].name, rerr)
-				}
-			}
-			return fmt.Errorf("%s init: %w", s.name, err)
-		}
-		initialized = append(initialized, s)
-	}
-	return nil
-}
-
 // AddPeerFiltering adds a rule to the firewall
 //
 // Comment will be ignored because some system this feature is not supported
@@ -191,13 +118,7 @@ func (m *Manager) AddPeerFiltering(
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if ip.To4() != nil {
-		return m.aclMgr.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
-	}
-	if !m.hasIPv6() {
-		return nil, fmt.Errorf("add peer filtering for %s: %w", ip, firewall.ErrIPv6NotInitialized)
-	}
-	return m.aclMgr6.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
+	return m.aclMgr.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
 }
 
 func (m *Manager) AddRouteFiltering(
@@ -211,48 +132,25 @@ func (m *Manager) AddRouteFiltering(
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if isIPv6RouteRule(sources, destination) {
-		if !m.hasIPv6() {
-			return nil, fmt.Errorf("add route filtering: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
+	if destination.IsPrefix() && !destination.Prefix.Addr().Is4() {
+		return nil, fmt.Errorf("unsupported IP version: %s", destination.Prefix.Addr().String())
 	}
 
 	return m.router.AddRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
 }
 
-func isIPv6RouteRule(sources []netip.Prefix, destination firewall.Network) bool {
-	if destination.IsPrefix() {
-		return destination.Prefix.Addr().Is6()
-	}
-	return len(sources) > 0 && sources[0].Addr().Is6()
-}
-
 // DeletePeerRule from the firewall by rule definition
 func (m *Manager) DeletePeerRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if m.hasIPv6() && isIPv6IptRule(rule) {
-		return m.aclMgr6.DeletePeerRule(rule)
-	}
 	return m.aclMgr.DeletePeerRule(rule)
 }
 
-func isIPv6IptRule(rule firewall.Rule) bool {
-	r, ok := rule.(*Rule)
-	return ok && r.v6
-}
-
-// DeleteRouteRule deletes a routing rule.
-// Route rules are keyed by content hash. Check v4 first, try v6 if not found.
 func (m *Manager) DeleteRouteRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if m.hasIPv6() && !m.router.hasRule(rule.ID()) {
-		return m.router6.DeleteRouteRule(rule)
-	}
 	return m.router.DeleteRouteRule(rule)
 }
 
@@ -268,65 +166,18 @@ func (m *Manager) AddNatRule(pair firewall.RouterPair) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if pair.Destination.IsPrefix() && pair.Destination.Prefix.Addr().Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("add NAT rule: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddNatRule(pair)
-	}
-
-	if err := m.router.AddNatRule(pair); err != nil {
-		return err
-	}
-
-	// Dynamic routes need NAT in both tables since resolved IPs can be
-	// either v4 or v6. This covers both DomainSet (modern) and the legacy
-	// wildcard 0.0.0.0/0 destination where the client resolves DNS.
-	if m.hasIPv6() && pair.Dynamic {
-		v6Pair := firewall.ToV6NatPair(pair)
-		if err := m.router6.AddNatRule(v6Pair); err != nil {
-			return fmt.Errorf("add v6 NAT rule: %w", err)
-		}
-	}
-
-	return nil
+	return m.router.AddNatRule(pair)
 }
 
 func (m *Manager) RemoveNatRule(pair firewall.RouterPair) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if pair.Destination.IsPrefix() && pair.Destination.Prefix.Addr().Is6() {
-		if !m.hasIPv6() {
-			return nil
-		}
-		return m.router6.RemoveNatRule(pair)
-	}
-
-	var merr *multierror.Error
-
-	if err := m.router.RemoveNatRule(pair); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("remove v4 NAT rule: %w", err))
-	}
-
-	if m.hasIPv6() && pair.Dynamic {
-		v6Pair := firewall.ToV6NatPair(pair)
-		if err := m.router6.RemoveNatRule(v6Pair); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("remove v6 NAT rule: %w", err))
-		}
-	}
-
-	return nberrors.FormatErrorOrNil(merr)
+	return m.router.RemoveNatRule(pair)
 }
 
 func (m *Manager) SetLegacyManagement(isLegacy bool) error {
-	if err := firewall.SetLegacyManagement(m.router, isLegacy); err != nil {
-		return err
-	}
-	if m.hasIPv6() {
-		return firewall.SetLegacyManagement(m.router6, isLegacy)
-	}
-	return nil
+	return firewall.SetLegacyManagement(m.router, isLegacy)
 }
 
 // Reset firewall to the default state
@@ -340,15 +191,6 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 		merr = multierror.Append(merr, fmt.Errorf("cleanup notrack chain: %w", err))
 	}
 
-	if m.hasIPv6() {
-		if err := m.aclMgr6.Reset(); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("reset v6 acl manager: %w", err))
-		}
-		if err := m.router6.Reset(); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("reset v6 router: %w", err))
-		}
-	}
-
 	if err := m.aclMgr.Reset(); err != nil {
 		merr = multierror.Append(merr, fmt.Errorf("reset acl manager: %w", err))
 	}
@@ -376,21 +218,24 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 // This is called when USPFilter wraps the native firewall, adding blanket accept
 // rules so that packet filtering is handled in userspace instead of by netfilter.
 func (m *Manager) AllowNetbird() error {
-	var merr *multierror.Error
-	if _, err := m.AddPeerFiltering(nil, net.IP{0, 0, 0, 0}, firewall.ProtocolALL, nil, nil, firewall.ActionAccept, ""); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("allow netbird v4 interface traffic: %w", err))
-	}
-	if m.hasIPv6() {
-		if _, err := m.AddPeerFiltering(nil, net.IPv6zero, firewall.ProtocolALL, nil, nil, firewall.ActionAccept, ""); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("allow netbird v6 interface traffic: %w", err))
-		}
+	_, err := m.AddPeerFiltering(
+		nil,
+		net.IP{0, 0, 0, 0},
+		firewall.ProtocolALL,
+		nil,
+		nil,
+		firewall.ActionAccept,
+		"",
+	)
+	if err != nil {
+		return fmt.Errorf("allow netbird interface traffic: %w", err)
 	}
 
 	if err := firewalld.TrustInterface(m.wgIface.Name()); err != nil {
 		log.Warnf("failed to trust interface in firewalld: %v", err)
 	}
 
-	return nberrors.FormatErrorOrNil(merr)
+	return nil
 }
 
 // Flush doesn't need to be implemented for this manager
@@ -420,12 +265,6 @@ func (m *Manager) AddDNATRule(rule firewall.ForwardRule) (firewall.Rule, error)
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if rule.TranslatedAddress.Is6() {
-		if !m.hasIPv6() {
-			return nil, fmt.Errorf("add DNAT rule: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddDNATRule(rule)
-	}
 	return m.router.AddDNATRule(rule)
 }
 
@@ -434,9 +273,6 @@ func (m *Manager) DeleteDNATRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if m.hasIPv6() && !m.router.hasRule(rule.ID()+dnatSuffix) {
-		return m.router6.DeleteDNATRule(rule)
-	}
 	return m.router.DeleteDNATRule(rule)
 }
 
@@ -445,82 +281,39 @@ func (m *Manager) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	var v4Prefixes, v6Prefixes []netip.Prefix
-	for _, p := range prefixes {
-		if p.Addr().Is6() {
-			v6Prefixes = append(v6Prefixes, p)
-		} else {
-			v4Prefixes = append(v4Prefixes, p)
-		}
-	}
-
-	if err := m.router.UpdateSet(set, v4Prefixes); err != nil {
-		return err
-	}
-
-	if m.hasIPv6() && len(v6Prefixes) > 0 {
-		if err := m.router6.UpdateSet(set, v6Prefixes); err != nil {
-			return fmt.Errorf("update v6 set: %w", err)
-		}
-	}
-
-	return nil
+	return m.router.UpdateSet(set, prefixes)
 }
 
 // AddInboundDNAT adds an inbound DNAT rule redirecting traffic from NetBird peers to local services.
-func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if localAddr.Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("add inbound DNAT: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
-	}
-	return m.router.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.router.AddInboundDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 // RemoveInboundDNAT removes an inbound DNAT rule.
-func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if localAddr.Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("remove inbound DNAT: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
-	}
-	return m.router.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.router.RemoveInboundDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 // AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
-func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if localAddr.Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("add output DNAT: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
-	}
-	return m.router.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.router.AddOutputDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 // RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
-func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if localAddr.Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("remove output DNAT: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
-	}
-	return m.router.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.router.RemoveOutputDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 const (

client/firewall/iptables/router_linux.go

@@ -54,10 +54,8 @@ const (
 	snatSuffix = "_snat"
 	fwdSuffix  = "_fwd"
 
-	// ipv4TCPHeaderSize is the minimum IPv4 (20) + TCP (20) header size for MSS calculation.
-	ipv4TCPHeaderSize = 40
-	// ipv6TCPHeaderSize is the minimum IPv6 (40) + TCP (20) header size for MSS calculation.
-	ipv6TCPHeaderSize = 60
+	// ipTCPHeaderMinSize represents minimum IP (20) + TCP (20) header size for MSS calculation
+	ipTCPHeaderMinSize = 40
 )
 
 type ruleInfo struct {
@@ -88,7 +86,6 @@ type router struct {
 	wgIface          iFaceMapper
 	legacyManagement bool
 	mtu              uint16
-	v6               bool
 
 	stateManager *statemanager.Manager
 	ipFwdState   *ipfwdstate.IPForwardingState
@@ -100,7 +97,6 @@ func newRouter(iptablesClient *iptables.IPTables, wgIface iFaceMapper, mtu uint1
 		rules:          make(map[string][]string),
 		wgIface:        wgIface,
 		mtu:            mtu,
-		v6:             iptablesClient.Proto() == iptables.ProtocolIPv6,
 		ipFwdState:     ipfwdstate.NewIPForwardingState(),
 	}
 
@@ -190,11 +186,6 @@ func (r *router) AddRouteFiltering(
 	return ruleKey, nil
 }
 
-func (r *router) hasRule(id string) bool {
-	_, ok := r.rules[id]
-	return ok
-}
-
 func (r *router) DeleteRouteRule(rule firewall.Rule) error {
 	ruleKey := rule.ID()
 
@@ -401,13 +392,9 @@ func (r *router) cleanUpDefaultForwardRules() error {
 
 	// Remove jump rules from built-in chains before deleting custom chains,
 	// otherwise the chain deletion fails with "device or resource busy".
-	if ok, err := r.iptablesClient.ChainExists(tableNat, chainNATOutput); err != nil {
-		return fmt.Errorf("check chain %s: %w", chainNATOutput, err)
-	} else if ok {
-		jumpRule := []string{"-j", chainNATOutput}
-		if err := r.iptablesClient.Delete(tableNat, "OUTPUT", jumpRule...); err != nil {
-			log.Debugf("clean OUTPUT jump rule: %v", err)
-		}
+	jumpRule := []string{"-j", chainNATOutput}
+	if err := r.iptablesClient.Delete(tableNat, "OUTPUT", jumpRule...); err != nil {
+		log.Debugf("clean OUTPUT jump rule: %v", err)
 	}
 
 	for _, chainInfo := range []struct {
@@ -447,12 +434,6 @@ func (r *router) createContainers() error {
 		{chainRTRDR, tableNat},
 		{chainRTMSSCLAMP, tableMangle},
 	} {
-		// Fallback: clear chains that survived an unclean shutdown.
-		if ok, _ := r.iptablesClient.ChainExists(chainInfo.table, chainInfo.chain); ok {
-			if err := r.iptablesClient.ClearAndDeleteChain(chainInfo.table, chainInfo.chain); err != nil {
-				log.Warnf("clear stale chain %s in %s: %v", chainInfo.chain, chainInfo.table, err)
-			}
-		}
 		if err := r.iptablesClient.NewChain(chainInfo.table, chainInfo.chain); err != nil {
 			return fmt.Errorf("create chain %s in table %s: %w", chainInfo.chain, chainInfo.table, err)
 		}
@@ -559,12 +540,9 @@ func (r *router) addPostroutingRules() error {
 }
 
 // addMSSClampingRules adds MSS clamping rules to prevent fragmentation for forwarded traffic.
+// TODO: Add IPv6 support
 func (r *router) addMSSClampingRules() error {
-	overhead := uint16(ipv4TCPHeaderSize)
-	if r.v6 {
-		overhead = ipv6TCPHeaderSize
-	}
-	mss := r.mtu - overhead
+	mss := r.mtu - ipTCPHeaderMinSize
 
 	// Add jump rule from FORWARD chain in mangle table to our custom chain
 	jumpRule := []string{
@@ -749,13 +727,8 @@ func (r *router) updateState() {
 	currentState.Lock()
 	defer currentState.Unlock()
 
-	if r.v6 {
-		currentState.RouteRules6 = r.rules
-		currentState.RouteIPsetCounter6 = r.ipsetCounter
-	} else {
-		currentState.RouteRules = r.rules
-		currentState.RouteIPsetCounter = r.ipsetCounter
-	}
+	currentState.RouteRules = r.rules
+	currentState.RouteIPsetCounter = r.ipsetCounter
 
 	if err := r.stateManager.UpdateState(currentState); err != nil {
 		log.Errorf("failed to update state: %v", err)
@@ -883,7 +856,7 @@ func (r *router) DeleteDNATRule(rule firewall.Rule) error {
 	}
 
 	if fwdRule, exists := r.rules[ruleKey+fwdSuffix]; exists {
-		if err := r.iptablesClient.Delete(tableFilter, chainRTFWDOUT, fwdRule...); err != nil {
+		if err := r.iptablesClient.Delete(tableFilter, chainRTFWDIN, fwdRule...); err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("delete forward rule: %w", err))
 		}
 		delete(r.rules, ruleKey+fwdSuffix)
@@ -910,7 +883,7 @@ func (r *router) genRouteRuleSpec(params routeFilteringRuleParams, sources []net
 	rule = append(rule, destExp...)
 
 	if params.Proto != firewall.ProtocolALL {
-		rule = append(rule, "-p", strings.ToLower(protoForFamily(params.Proto, r.v6)))
+		rule = append(rule, "-p", strings.ToLower(string(params.Proto)))
 		rule = append(rule, applyPort("--sport", params.SPort)...)
 		rule = append(rule, applyPort("--dport", params.DPort)...)
 	}
@@ -927,12 +900,11 @@ func (r *router) applyNetwork(flag string, network firewall.Network, prefixes []
 	}
 
 	if network.IsSet() {
-		name := r.ipsetName(network.Set.HashedName())
-		if _, err := r.ipsetCounter.Increment(name, prefixes); err != nil {
+		if _, err := r.ipsetCounter.Increment(network.Set.HashedName(), prefixes); err != nil {
 			return nil, fmt.Errorf("create or get ipset: %w", err)
 		}
 
-		return []string{"-m", "set", matchSet, name, direction}, nil
+		return []string{"-m", "set", matchSet, network.Set.HashedName(), direction}, nil
 	}
 	if network.IsPrefix() {
 		return []string{flag, network.Prefix.String()}, nil
@@ -943,23 +915,27 @@ func (r *router) applyNetwork(flag string, network firewall.Network, prefixes []
 }
 
 func (r *router) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
-	name := r.ipsetName(set.HashedName())
 	var merr *multierror.Error
 	for _, prefix := range prefixes {
-		if err := r.addPrefixToIPSet(name, prefix); err != nil {
+		// TODO: Implement IPv6 support
+		if prefix.Addr().Is6() {
+			log.Tracef("skipping IPv6 prefix %s: IPv6 support not yet implemented", prefix)
+			continue
+		}
+		if err := r.addPrefixToIPSet(set.HashedName(), prefix); err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("add prefix to ipset: %w", err))
 		}
 	}
 	if merr == nil {
-		log.Debugf("updated set %s with prefixes %v", name, prefixes)
+		log.Debugf("updated set %s with prefixes %v", set.HashedName(), prefixes)
 	}
 
 	return nberrors.FormatErrorOrNil(merr)
 }
 
 // AddInboundDNAT adds an inbound DNAT rule redirecting traffic from NetBird peers to local services.
-func (r *router) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
-	ruleID := fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort)
+func (r *router) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	ruleID := fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
 
 	if _, exists := r.rules[ruleID]; exists {
 		return nil
@@ -967,12 +943,12 @@ func (r *router) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol
 
 	dnatRule := []string{
 		"-i", r.wgIface.Name(),
-		"-p", strings.ToLower(protoForFamily(protocol, r.v6)),
-		"--dport", strconv.Itoa(int(originalPort)),
+		"-p", strings.ToLower(string(protocol)),
+		"--dport", strconv.Itoa(int(sourcePort)),
 		"-d", localAddr.String(),
 		"-m", "addrtype", "--dst-type", "LOCAL",
 		"-j", "DNAT",
-		"--to-destination", ":" + strconv.Itoa(int(translatedPort)),
+		"--to-destination", ":" + strconv.Itoa(int(targetPort)),
 	}
 
 	ruleInfo := ruleInfo{
@@ -991,8 +967,8 @@ func (r *router) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol
 }
 
 // RemoveInboundDNAT removes an inbound DNAT rule.
-func (r *router) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
-	ruleID := fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort)
+func (r *router) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	ruleID := fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
 
 	if dnatRule, exists := r.rules[ruleID]; exists {
 		if err := r.iptablesClient.Delete(tableNat, chainRTRDR, dnatRule...); err != nil {
@@ -1037,8 +1013,8 @@ func (r *router) ensureNATOutputChain() error {
 }
 
 // AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
-func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
-	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort)
+func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
 
 	if _, exists := r.rules[ruleID]; exists {
 		return nil
@@ -1049,11 +1025,11 @@ func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol,
 	}
 
 	dnatRule := []string{
-		"-p", strings.ToLower(protoForFamily(protocol, localAddr.Is6())),
-		"--dport", strconv.Itoa(int(originalPort)),
+		"-p", strings.ToLower(string(protocol)),
+		"--dport", strconv.Itoa(int(sourcePort)),
 		"-d", localAddr.String(),
 		"-j", "DNAT",
-		"--to-destination", ":" + strconv.Itoa(int(translatedPort)),
+		"--to-destination", ":" + strconv.Itoa(int(targetPort)),
 	}
 
 	if err := r.iptablesClient.Append(tableNat, chainNATOutput, dnatRule...); err != nil {
@@ -1066,8 +1042,8 @@ func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol,
 }
 
 // RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
-func (r *router) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
-	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort)
+func (r *router) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
 
 	if dnatRule, exists := r.rules[ruleID]; exists {
 		if err := r.iptablesClient.Delete(tableNat, chainNATOutput, dnatRule...); err != nil {
@@ -1100,22 +1076,10 @@ func applyPort(flag string, port *firewall.Port) []string {
 	return []string{flag, strconv.Itoa(int(port.Values[0]))}
 }
 
-// ipsetName returns the ipset name, suffixed with "-v6" for the v6 router
-// to avoid collisions since ipsets are global in the kernel.
-func (r *router) ipsetName(name string) string {
-	if r.v6 {
-		return name + "-v6"
-	}
-	return name
-}
-
 func (r *router) createIPSet(name string) error {
 	opts := ipset.CreateOptions{
 		Replace: true,
 	}
-	if r.v6 {
-		opts.Family = ipset.FamilyIPV6
-	}
 
 	if err := ipset.Create(name, ipset.TypeHashNet, opts); err != nil {
 		return fmt.Errorf("create ipset %s: %w", name, err)

client/firewall/iptables/rule.go

@@ -9,7 +9,6 @@ type Rule struct {
 	mangleSpecs []string
 	ip          string
 	chain       string
-	v6          bool
 }
 
 // GetRuleID returns the rule id

client/firewall/iptables/state_linux.go

@@ -4,8 +4,6 @@ import (
 	"fmt"
 	"sync"
 
-	log "github.com/sirupsen/logrus"
-
 	"github.com/netbirdio/netbird/client/iface"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 )
@@ -34,12 +32,6 @@ type ShutdownState struct {
 
 	ACLEntries    aclEntries  `json:"acl_entries,omitempty"`
 	ACLIPsetStore *ipsetStore `json:"acl_ipset_store,omitempty"`
-
-	// IPv6 counterparts
-	RouteRules6        routeRules    `json:"route_rules_v6,omitempty"`
-	RouteIPsetCounter6 *ipsetCounter `json:"route_ipset_counter_v6,omitempty"`
-	ACLEntries6        aclEntries    `json:"acl_entries_v6,omitempty"`
-	ACLIPsetStore6     *ipsetStore   `json:"acl_ipset_store_v6,omitempty"`
 }
 
 func (s *ShutdownState) Name() string {
@@ -70,28 +62,6 @@ func (s *ShutdownState) Cleanup() error {
 		ipt.aclMgr.ipsetStore = s.ACLIPsetStore
 	}
 
-	// Clean up v6 state even if the current run has no IPv6.
-	// The previous run may have left ip6tables rules behind.
-	if !ipt.hasIPv6() {
-		if err := ipt.createIPv6Components(s.InterfaceState, mtu); err != nil {
-			log.Warnf("failed to create v6 components for cleanup: %v", err)
-		}
-	}
-	if ipt.hasIPv6() {
-		if s.RouteRules6 != nil {
-			ipt.router6.rules = s.RouteRules6
-		}
-		if s.RouteIPsetCounter6 != nil {
-			ipt.router6.ipsetCounter.LoadData(s.RouteIPsetCounter6)
-		}
-		if s.ACLEntries6 != nil {
-			ipt.aclMgr6.entries = s.ACLEntries6
-		}
-		if s.ACLIPsetStore6 != nil {
-			ipt.aclMgr6.ipsetStore = s.ACLIPsetStore6
-		}
-	}
-
 	if err := ipt.Close(nil); err != nil {
 		return fmt.Errorf("reset iptables manager: %w", err)
 	}

client/firewall/manager/firewall.go

@@ -1,7 +1,6 @@
 package manager
 
 import (
-	"errors"
 	"fmt"
 	"net"
 	"net/netip"
@@ -12,10 +11,6 @@ import (
 	"github.com/netbirdio/netbird/client/internal/statemanager"
 )
 
-// ErrIPv6NotInitialized is returned when an IPv6 address is passed to a firewall
-// method but the IPv6 firewall components were not initialized.
-var ErrIPv6NotInitialized = errors.New("IPv6 firewall not initialized")
-
 const (
 	ForwardingFormatPrefix = "netbird-fwd-"
 	ForwardingFormat       = "netbird-fwd-%s-%t"
@@ -169,16 +164,18 @@ type Manager interface {
 	UpdateSet(hash Set, prefixes []netip.Prefix) error
 
 	// AddInboundDNAT adds an inbound DNAT rule redirecting traffic from NetBird peers to local services
-	AddInboundDNAT(localAddr netip.Addr, protocol Protocol, originalPort, translatedPort uint16) error
+	AddInboundDNAT(localAddr netip.Addr, protocol Protocol, sourcePort, targetPort uint16) error
 
 	// RemoveInboundDNAT removes inbound DNAT rule
-	RemoveInboundDNAT(localAddr netip.Addr, protocol Protocol, originalPort, translatedPort uint16) error
+	RemoveInboundDNAT(localAddr netip.Addr, protocol Protocol, sourcePort, targetPort uint16) error
 
 	// AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
-	AddOutputDNAT(localAddr netip.Addr, protocol Protocol, originalPort, translatedPort uint16) error
+	// localAddr must be IPv4; the underlying iptables/nftables backends are IPv4-only.
+	AddOutputDNAT(localAddr netip.Addr, protocol Protocol, sourcePort, targetPort uint16) error
 
 	// RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
-	RemoveOutputDNAT(localAddr netip.Addr, protocol Protocol, originalPort, translatedPort uint16) error
+	// localAddr must be IPv4; the underlying iptables/nftables backends are IPv4-only.
+	RemoveOutputDNAT(localAddr netip.Addr, protocol Protocol, sourcePort, targetPort uint16) error
 
 	// SetupEBPFProxyNoTrack creates static notrack rules for eBPF proxy loopback traffic.
 	// This prevents conntrack from interfering with WireGuard proxy communication.

client/firewall/manager/routerpair.go

@@ -1,8 +1,6 @@
 package manager
 
 import (
-	"net/netip"
-
 	"github.com/netbirdio/netbird/route"
 )
 
@@ -12,10 +10,6 @@ type RouterPair struct {
 	Destination Network
 	Masquerade  bool
 	Inverse     bool
-	// Dynamic indicates the route is domain-based. NAT rules for dynamic
-	// routes are duplicated to the v6 table so that resolved AAAA records
-	// are masqueraded correctly.
-	Dynamic bool
 }
 
 func GetInversePair(pair RouterPair) RouterPair {
@@ -26,17 +20,5 @@ func GetInversePair(pair RouterPair) RouterPair {
 		Destination: pair.Source,
 		Masquerade:  pair.Masquerade,
 		Inverse:     true,
-		Dynamic:     pair.Dynamic,
 	}
 }
-
-// ToV6NatPair creates a v6 counterpart of a v4 NAT pair with `::/0` source
-// and, for prefix destinations, `::/0` destination.
-func ToV6NatPair(pair RouterPair) RouterPair {
-	v6 := pair
-	v6.Source = Network{Prefix: netip.PrefixFrom(netip.IPv6Unspecified(), 0)}
-	if v6.Destination.IsPrefix() {
-		v6.Destination = Network{Prefix: netip.PrefixFrom(netip.IPv6Unspecified(), 0)}
-	}
-	return v6
-}

client/firewall/nftables/acl_linux.go

@@ -33,12 +33,15 @@ const (
 
 const flushError = "flush: %w"
 
+var (
+	anyIP = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
+)
+
 type AclManager struct {
 	rConn              *nftables.Conn
 	sConn              *nftables.Conn
 	wgIface            iFaceMapper
 	routingFwChainName string
-	af                 addrFamily
 
 	workTable       *nftables.Table
 	chainInputRules *nftables.Chain
@@ -64,7 +67,6 @@ func newAclManager(table *nftables.Table, wgIface iFaceMapper, routingFwChainNam
 		wgIface:            wgIface,
 		workTable:          table,
 		routingFwChainName: routingFwChainName,
-		af:                 familyForAddr(table.Family == nftables.TableFamilyIPv4),
 
 		ipsetStore: newIpsetStore(),
 		rules:      make(map[string]*Rule),
@@ -143,7 +145,7 @@ func (m *AclManager) DeletePeerRule(rule firewall.Rule) error {
 	}
 
 	if _, ok := ips[r.ip.String()]; ok {
-		err := m.sConn.SetDeleteElements(r.nftSet, []nftables.SetElement{{Key: ipToBytes(r.ip, m.af)}})
+		err := m.sConn.SetDeleteElements(r.nftSet, []nftables.SetElement{{Key: r.ip.To4()}})
 		if err != nil {
 			log.Errorf("delete elements for set %q: %v", r.nftSet.Name, err)
 		}
@@ -252,11 +254,11 @@ func (m *AclManager) addIOFiltering(
 		expressions = append(expressions, &expr.Payload{
 			DestRegister: 1,
 			Base:         expr.PayloadBaseNetworkHeader,
-			Offset:       m.af.protoOffset,
+			Offset:       uint32(9),
 			Len:          uint32(1),
 		})
 
-		protoData, err := m.af.protoNum(proto)
+		protoData, err := protoToInt(proto)
 		if err != nil {
 			return nil, fmt.Errorf("convert protocol to number: %v", err)
 		}
@@ -268,16 +270,19 @@ func (m *AclManager) addIOFiltering(
 		})
 	}
 
-	rawIP := ipToBytes(ip, m.af)
+	rawIP := ip.To4()
 	// check if rawIP contains zeroed IPv4 0.0.0.0 value
 	// in that case not add IP match expression into the rule definition
-	if slices.ContainsFunc(rawIP, func(v byte) bool { return v != 0 }) {
+	if !bytes.HasPrefix(anyIP, rawIP) {
+		// source address position
+		addrOffset := uint32(12)
+
 		expressions = append(expressions,
 			&expr.Payload{
 				DestRegister: 1,
 				Base:         expr.PayloadBaseNetworkHeader,
-				Offset:       m.af.srcAddrOffset,
-				Len:          m.af.addrLen,
+				Offset:       addrOffset,
+				Len:          4,
 			},
 		)
 		// add individual IP for match if no ipset defined
@@ -582,7 +587,7 @@ func (m *AclManager) addJumpRule(chain *nftables.Chain, to string, ifaceKey expr
 
 func (m *AclManager) addIpToSet(ipsetName string, ip net.IP) (*nftables.Set, error) {
 	ipset, err := m.rConn.GetSetByName(m.workTable, ipsetName)
-	rawIP := ipToBytes(ip, m.af)
+	rawIP := ip.To4()
 	if err != nil {
 		if ipset, err = m.createSet(m.workTable, ipsetName); err != nil {
 			return nil, fmt.Errorf("get set name: %v", err)
@@ -614,7 +619,7 @@ func (m *AclManager) createSet(table *nftables.Table, name string) (*nftables.Se
 		Name:    name,
 		Table:   table,
 		Dynamic: true,
-		KeyType: m.af.setKeyType,
+		KeyType: nftables.TypeIPAddr,
 	}
 
 	if err := m.rConn.AddSet(ipset, nil); err != nil {
@@ -702,12 +707,15 @@ func ifname(n string) []byte {
 	return b
 }
 
-
-// ipToBytes converts net.IP to the correct byte length for the address family.
-func ipToBytes(ip net.IP, af addrFamily) []byte {
-	if af.addrLen == 4 {
-		return ip.To4()
+func protoToInt(protocol firewall.Protocol) (uint8, error) {
+	switch protocol {
+	case firewall.ProtocolTCP:
+		return unix.IPPROTO_TCP, nil
+	case firewall.ProtocolUDP:
+		return unix.IPPROTO_UDP, nil
+	case firewall.ProtocolICMP:
+		return unix.IPPROTO_ICMP, nil
 	}
-	return ip.To16()
-}
 
+	return 0, fmt.Errorf("unsupported protocol: %s", protocol)
+}

client/firewall/nftables/addr_family_linux.go

@@ -1,81 +0,0 @@
-package nftables
-
-import (
-	"fmt"
-	"net"
-
-	"github.com/google/nftables"
-	"golang.org/x/sys/unix"
-
-	firewall "github.com/netbirdio/netbird/client/firewall/manager"
-)
-
-var (
-	// afIPv4 defines IPv4 header layout and nftables types.
-	afIPv4 = addrFamily{
-		protoOffset:   9,
-		srcAddrOffset: 12,
-		dstAddrOffset: 16,
-		addrLen:       net.IPv4len,
-		totalBits:     8 * net.IPv4len,
-		setKeyType:    nftables.TypeIPAddr,
-		tableFamily:   nftables.TableFamilyIPv4,
-		icmpProto:     unix.IPPROTO_ICMP,
-	}
-	// afIPv6 defines IPv6 header layout and nftables types.
-	afIPv6 = addrFamily{
-		protoOffset:   6,
-		srcAddrOffset: 8,
-		dstAddrOffset: 24,
-		addrLen:       net.IPv6len,
-		totalBits:     8 * net.IPv6len,
-		setKeyType:    nftables.TypeIP6Addr,
-		tableFamily:   nftables.TableFamilyIPv6,
-		icmpProto:     unix.IPPROTO_ICMPV6,
-	}
-)
-
-// addrFamily holds protocol-specific constants for nftables expression building.
-type addrFamily struct {
-	// protoOffset is the IP header offset for the protocol/next-header field (9 for v4, 6 for v6)
-	protoOffset uint32
-	// srcAddrOffset is the IP header offset for the source address (12 for v4, 8 for v6)
-	srcAddrOffset uint32
-	// dstAddrOffset is the IP header offset for the destination address (16 for v4, 24 for v6)
-	dstAddrOffset uint32
-	// addrLen is the byte length of addresses (4 for v4, 16 for v6)
-	addrLen uint32
-	// totalBits is the address size in bits (32 for v4, 128 for v6)
-	totalBits int
-	// setKeyType is the nftables set data type for addresses
-	setKeyType nftables.SetDatatype
-	// tableFamily is the nftables table family
-	tableFamily nftables.TableFamily
-	// icmpProto is the ICMP protocol number for this family (1 for v4, 58 for v6)
-	icmpProto uint8
-}
-
-// familyForAddr returns the address family for the given IP.
-func familyForAddr(is4 bool) addrFamily {
-	if is4 {
-		return afIPv4
-	}
-	return afIPv6
-}
-
-// protoNum converts a firewall protocol to the IP protocol number,
-// using the correct ICMP variant for the address family.
-func (af addrFamily) protoNum(protocol firewall.Protocol) (uint8, error) {
-	switch protocol {
-	case firewall.ProtocolTCP:
-		return unix.IPPROTO_TCP, nil
-	case firewall.ProtocolUDP:
-		return unix.IPPROTO_UDP, nil
-	case firewall.ProtocolICMP:
-		return af.icmpProto, nil
-	case firewall.ProtocolALL:
-		return 0, nil
-	default:
-		return 0, fmt.Errorf("unsupported protocol: %s", protocol)
-	}
-}

client/firewall/nftables/external_chain_monitor_integration_linux_test.go

@@ -1,76 +0,0 @@
-//go:build linux
-
-package nftables
-
-import (
-	"os"
-	"sync/atomic"
-	"testing"
-	"time"
-
-	"github.com/google/nftables"
-	"github.com/stretchr/testify/require"
-)
-
-// TestExternalChainMonitorRootIntegration verifies that adding a new chain
-// in an external (non-netbird) filter table triggers the reconciler.
-// Requires CAP_NET_ADMIN; skip otherwise.
-func TestExternalChainMonitorRootIntegration(t *testing.T) {
-	if os.Geteuid() != 0 {
-		t.Skip("root required")
-	}
-
-	calls := make(chan struct{}, 8)
-	var count atomic.Int32
-	rec := &countingReconciler{calls: calls, count: &count}
-
-	m := newExternalChainMonitor(rec)
-	m.start()
-	t.Cleanup(m.stop)
-
-	// Give the netlink subscription a moment to register.
-	time.Sleep(200 * time.Millisecond)
-
-	conn := &nftables.Conn{}
-	table := conn.AddTable(&nftables.Table{
-		Name:   "nbmon_integration_test",
-		Family: nftables.TableFamilyINet,
-	})
-	t.Cleanup(func() {
-		cleanup := &nftables.Conn{}
-		cleanup.DelTable(table)
-		_ = cleanup.Flush()
-	})
-
-	chain := conn.AddChain(&nftables.Chain{
-		Name:     "filter_INPUT",
-		Table:    table,
-		Hooknum:  nftables.ChainHookInput,
-		Priority: nftables.ChainPriorityFilter,
-		Type:     nftables.ChainTypeFilter,
-	})
-	_ = chain
-	require.NoError(t, conn.Flush(), "create external test chain")
-
-	select {
-	case <-calls:
-		// success
-	case <-time.After(3 * time.Second):
-		t.Fatalf("reconcile was not invoked after creating an external chain")
-	}
-	require.GreaterOrEqual(t, count.Load(), int32(1))
-}
-
-type countingReconciler struct {
-	calls chan struct{}
-	count *atomic.Int32
-}
-
-func (c *countingReconciler) reconcileExternalChains() error {
-	c.count.Add(1)
-	select {
-	case c.calls <- struct{}{}:
-	default:
-	}
-	return nil
-}

client/firewall/nftables/external_chain_monitor_linux.go

@@ -1,199 +0,0 @@
-package nftables
-
-import (
-	"context"
-	"errors"
-	"fmt"
-	"sync"
-	"time"
-
-	"github.com/cenkalti/backoff/v4"
-	"github.com/google/nftables"
-	log "github.com/sirupsen/logrus"
-)
-
-const (
-	externalMonitorReconcileDelay = 500 * time.Millisecond
-	externalMonitorInitInterval   = 5 * time.Second
-	externalMonitorMaxInterval    = 5 * time.Minute
-	externalMonitorRandomization  = 0.5
-)
-
-// externalChainReconciler re-applies passthrough accept rules to external
-// nftables chains. Implementations must be safe to call from the monitor
-// goroutine; the Manager locks its mutex internally.
-type externalChainReconciler interface {
-	reconcileExternalChains() error
-}
-
-// externalChainMonitor watches nftables netlink events and triggers a
-// reconcile when a new table or chain appears (e.g. after
-// `firewall-cmd --reload`). Netlink errors trigger exponential-backoff
-// reconnect.
-type externalChainMonitor struct {
-	reconciler externalChainReconciler
-
-	mu     sync.Mutex
-	cancel context.CancelFunc
-	done   chan struct{}
-}
-
-func newExternalChainMonitor(r externalChainReconciler) *externalChainMonitor {
-	return &externalChainMonitor{reconciler: r}
-}
-
-func (m *externalChainMonitor) start() {
-	m.mu.Lock()
-	defer m.mu.Unlock()
-
-	if m.cancel != nil {
-		return
-	}
-
-	ctx, cancel := context.WithCancel(context.Background())
-	m.cancel = cancel
-	m.done = make(chan struct{})
-
-	go m.run(ctx)
-}
-
-func (m *externalChainMonitor) stop() {
-	m.mu.Lock()
-	cancel := m.cancel
-	done := m.done
-	m.cancel = nil
-	m.done = nil
-	m.mu.Unlock()
-
-	if cancel == nil {
-		return
-	}
-	cancel()
-	<-done
-}
-
-func (m *externalChainMonitor) run(ctx context.Context) {
-	defer close(m.done)
-
-	bo := &backoff.ExponentialBackOff{
-		InitialInterval:     externalMonitorInitInterval,
-		RandomizationFactor: externalMonitorRandomization,
-		Multiplier:          backoff.DefaultMultiplier,
-		MaxInterval:         externalMonitorMaxInterval,
-		MaxElapsedTime:      0,
-		Clock:               backoff.SystemClock,
-	}
-	bo.Reset()
-
-	for ctx.Err() == nil {
-		err := m.watch(ctx)
-		if ctx.Err() != nil {
-			return
-		}
-
-		delay := bo.NextBackOff()
-		log.Warnf("external chain monitor: %v, reconnecting in %s", err, delay)
-		select {
-		case <-ctx.Done():
-			return
-		case <-time.After(delay):
-		}
-	}
-}
-
-func (m *externalChainMonitor) watch(ctx context.Context) error {
-	events, closeMon, err := m.subscribe()
-	if err != nil {
-		return err
-	}
-	defer closeMon()
-
-	debounce := time.NewTimer(time.Hour)
-	if !debounce.Stop() {
-		<-debounce.C
-	}
-	defer debounce.Stop()
-
-	pending := false
-	for {
-		select {
-		case <-ctx.Done():
-			return nil
-		case <-debounce.C:
-			pending = false
-			m.reconcile()
-		case ev, ok := <-events:
-			if !ok {
-				return errors.New("monitor channel closed")
-			}
-			if ev.Error != nil {
-				return fmt.Errorf("monitor event: %w", ev.Error)
-			}
-			if !isRelevantMonitorEvent(ev) {
-				continue
-			}
-			resetDebounce(debounce, pending)
-			pending = true
-		}
-	}
-}
-
-func (m *externalChainMonitor) subscribe() (chan *nftables.MonitorEvent, func(), error) {
-	conn := &nftables.Conn{}
-	mon := nftables.NewMonitor(
-		nftables.WithMonitorAction(nftables.MonitorActionNew),
-		nftables.WithMonitorObject(nftables.MonitorObjectChains|nftables.MonitorObjectTables),
-	)
-	events, err := conn.AddMonitor(mon)
-	if err != nil {
-		return nil, nil, fmt.Errorf("add netlink monitor: %w", err)
-	}
-	return events, func() { _ = mon.Close() }, nil
-}
-
-// resetDebounce reschedules a pending debounce timer without leaking a stale
-// fire on its channel. pending must reflect whether the timer is armed.
-func resetDebounce(t *time.Timer, pending bool) {
-	if pending && !t.Stop() {
-		select {
-		case <-t.C:
-		default:
-		}
-	}
-	t.Reset(externalMonitorReconcileDelay)
-}
-
-func (m *externalChainMonitor) reconcile() {
-	if err := m.reconciler.reconcileExternalChains(); err != nil {
-		log.Warnf("reconcile external chain rules: %v", err)
-	}
-}
-
-// isRelevantMonitorEvent returns true for table/chain creation events on
-// families we care about. The reconciler filters to actual external filter
-// chains.
-func isRelevantMonitorEvent(ev *nftables.MonitorEvent) bool {
-	switch ev.Type {
-	case nftables.MonitorEventTypeNewChain:
-		chain, ok := ev.Data.(*nftables.Chain)
-		if !ok || chain == nil || chain.Table == nil {
-			return false
-		}
-		return isMonitoredFamily(chain.Table.Family)
-	case nftables.MonitorEventTypeNewTable:
-		table, ok := ev.Data.(*nftables.Table)
-		if !ok || table == nil {
-			return false
-		}
-		return isMonitoredFamily(table.Family)
-	}
-	return false
-}
-
-func isMonitoredFamily(family nftables.TableFamily) bool {
-	switch family {
-	case nftables.TableFamilyIPv4, nftables.TableFamilyIPv6, nftables.TableFamilyINet:
-		return true
-	}
-	return false
-}

client/firewall/nftables/external_chain_monitor_linux_test.go

@@ -1,137 +0,0 @@
-package nftables
-
-import (
-	"testing"
-
-	"github.com/google/nftables"
-	"github.com/stretchr/testify/assert"
-)
-
-func TestIsMonitoredFamily(t *testing.T) {
-	tests := []struct {
-		family nftables.TableFamily
-		want   bool
-	}{
-		{nftables.TableFamilyIPv4, true},
-		{nftables.TableFamilyIPv6, true},
-		{nftables.TableFamilyINet, true},
-		{nftables.TableFamilyARP, false},
-		{nftables.TableFamilyBridge, false},
-		{nftables.TableFamilyNetdev, false},
-		{nftables.TableFamilyUnspecified, false},
-	}
-	for _, tc := range tests {
-		assert.Equal(t, tc.want, isMonitoredFamily(tc.family), "family=%d", tc.family)
-	}
-}
-
-func TestIsRelevantMonitorEvent(t *testing.T) {
-	inetTable := &nftables.Table{Name: "firewalld", Family: nftables.TableFamilyINet}
-	ipTable := &nftables.Table{Name: "filter", Family: nftables.TableFamilyIPv4}
-	arpTable := &nftables.Table{Name: "arp", Family: nftables.TableFamilyARP}
-
-	tests := []struct {
-		name string
-		ev   *nftables.MonitorEvent
-		want bool
-	}{
-		{
-			name: "new chain in inet firewalld",
-			ev: &nftables.MonitorEvent{
-				Type: nftables.MonitorEventTypeNewChain,
-				Data: &nftables.Chain{Name: "filter_INPUT", Table: inetTable},
-			},
-			want: true,
-		},
-		{
-			name: "new chain in ip filter",
-			ev: &nftables.MonitorEvent{
-				Type: nftables.MonitorEventTypeNewChain,
-				Data: &nftables.Chain{Name: "INPUT", Table: ipTable},
-			},
-			want: true,
-		},
-		{
-			name: "new chain in unwatched arp family",
-			ev: &nftables.MonitorEvent{
-				Type: nftables.MonitorEventTypeNewChain,
-				Data: &nftables.Chain{Name: "x", Table: arpTable},
-			},
-			want: false,
-		},
-		{
-			name: "new table inet",
-			ev: &nftables.MonitorEvent{
-				Type: nftables.MonitorEventTypeNewTable,
-				Data: inetTable,
-			},
-			want: true,
-		},
-		{
-			name: "del chain (we only act on new)",
-			ev: &nftables.MonitorEvent{
-				Type: nftables.MonitorEventTypeDelChain,
-				Data: &nftables.Chain{Name: "filter_INPUT", Table: inetTable},
-			},
-			want: false,
-		},
-		{
-			name: "chain with nil table",
-			ev: &nftables.MonitorEvent{
-				Type: nftables.MonitorEventTypeNewChain,
-				Data: &nftables.Chain{Name: "x"},
-			},
-			want: false,
-		},
-		{
-			name: "nil data",
-			ev: &nftables.MonitorEvent{
-				Type: nftables.MonitorEventTypeNewChain,
-				Data: (*nftables.Chain)(nil),
-			},
-			want: false,
-		},
-	}
-
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			assert.Equal(t, tc.want, isRelevantMonitorEvent(tc.ev))
-		})
-	}
-}
-
-// fakeReconciler records reconcile invocations for debounce tests.
-type fakeReconciler struct {
-	calls chan struct{}
-}
-
-func (f *fakeReconciler) reconcileExternalChains() error {
-	f.calls <- struct{}{}
-	return nil
-}
-
-func TestExternalChainMonitorStopWithoutStart(t *testing.T) {
-	m := newExternalChainMonitor(&fakeReconciler{calls: make(chan struct{}, 1)})
-	// Must not panic or block.
-	m.stop()
-}
-
-func TestExternalChainMonitorDoubleStart(t *testing.T) {
-	// start() twice should be a no-op; stop() cleans up once.
-	// We avoid exercising the netlink watch loop here because it needs root.
-	m := newExternalChainMonitor(&fakeReconciler{calls: make(chan struct{}, 1)})
-
-	// Replace run with a stub that just waits for cancel, so start() stays
-	// deterministic without opening a netlink socket.
-	origDone := make(chan struct{})
-	m.done = origDone
-	m.cancel = func() { close(origDone) }
-
-	// Second start should be a no-op (cancel already set).
-	m.start()
-	assert.NotNil(t, m.cancel)
-
-	m.stop()
-	assert.Nil(t, m.cancel)
-	assert.Nil(t, m.done)
-}

client/firewall/nftables/manager_linux.go

@@ -11,11 +11,9 @@ import (
 	"github.com/google/nftables"
 	"github.com/google/nftables/binaryutil"
 	"github.com/google/nftables/expr"
-	"github.com/hashicorp/go-multierror"
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/sys/unix"
 
-	nberrors "github.com/netbirdio/netbird/client/errors"
 	"github.com/netbirdio/netbird/client/firewall/firewalld"
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
@@ -51,17 +49,10 @@ type Manager struct {
 	rConn   *nftables.Conn
 	wgIface iFaceMapper
 
-	router     *router
-	aclManager *AclManager
-
-	// IPv6 counterparts, nil when no v6 overlay
-	router6     *router
-	aclManager6 *AclManager
-
+	router                 *router
+	aclManager             *AclManager
 	notrackOutputChain     *nftables.Chain
 	notrackPreroutingChain *nftables.Chain
-
-	extMonitor *externalChainMonitor
 }
 
 // Create nftables firewall manager
@@ -71,8 +62,7 @@ func Create(wgIface iFaceMapper, mtu uint16) (*Manager, error) {
 		wgIface: wgIface,
 	}
 
-	tableName := getTableName()
-	workTable := &nftables.Table{Name: tableName, Family: nftables.TableFamilyIPv4}
+	workTable := &nftables.Table{Name: getTableName(), Family: nftables.TableFamilyIPv4}
 
 	var err error
 	m.router, err = newRouter(workTable, wgIface, mtu)
@@ -85,137 +75,35 @@ func Create(wgIface iFaceMapper, mtu uint16) (*Manager, error) {
 		return nil, fmt.Errorf("create acl manager: %w", err)
 	}
 
-	if wgIface.Address().HasIPv6() {
-		if err := m.createIPv6Components(tableName, wgIface, mtu); err != nil {
-			return nil, fmt.Errorf("create IPv6 firewall: %w", err)
-		}
-	}
-
-	m.extMonitor = newExternalChainMonitor(m)
-
 	return m, nil
 }
 
-func (m *Manager) createIPv6Components(tableName string, wgIface iFaceMapper, mtu uint16) error {
-	workTable6 := &nftables.Table{Name: tableName, Family: nftables.TableFamilyIPv6}
-
-	var err error
-	m.router6, err = newRouter(workTable6, wgIface, mtu)
-	if err != nil {
-		return fmt.Errorf("create v6 router: %w", err)
-	}
-
-	// Share the same IP forwarding state with the v4 router, since
-	// EnableIPForwarding controls both v4 and v6 sysctls.
-	m.router6.ipFwdState = m.router.ipFwdState
-
-	m.aclManager6, err = newAclManager(workTable6, wgIface, chainNameRoutingFw)
-	if err != nil {
-		return fmt.Errorf("create v6 acl manager: %w", err)
-	}
-
-	return nil
-}
-
-// hasIPv6 reports whether the manager has IPv6 components initialized.
-func (m *Manager) hasIPv6() bool {
-	return m.router6 != nil
-}
-
-func (m *Manager) initIPv6() error {
-	workTable6, err := m.createWorkTableFamily(nftables.TableFamilyIPv6)
-	if err != nil {
-		return fmt.Errorf("create v6 work table: %w", err)
-	}
-
-	if err := m.router6.init(workTable6); err != nil {
-		return fmt.Errorf("v6 router init: %w", err)
-	}
-
-	if err := m.aclManager6.init(workTable6); err != nil {
-		return fmt.Errorf("v6 acl manager init: %w", err)
-	}
-
-	return nil
-}
-
 // Init nftables firewall manager
 func (m *Manager) Init(stateManager *statemanager.Manager) error {
-	if err := m.initFirewall(); err != nil {
-		return err
-	}
-
-	m.persistState(stateManager)
-
-	// Start after initFirewall has installed the baseline external-chain
-	// accept rules. start() is idempotent across Init/Close/Init cycles.
-	m.extMonitor.start()
-
-	return nil
-}
-
-// reconcileExternalChains re-applies passthrough accept rules to external
-// filter chains for both IPv4 and IPv6 routers. Called by the monitor when
-// tables or chains appear (e.g. after firewalld reloads).
-func (m *Manager) reconcileExternalChains() error {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
-
-	var merr *multierror.Error
-	if m.router != nil {
-		if err := m.router.acceptExternalChainsRules(); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("v4: %w", err))
-		}
-	}
-	if m.hasIPv6() {
-		if err := m.router6.acceptExternalChainsRules(); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("v6: %w", err))
-		}
-	}
-	return nberrors.FormatErrorOrNil(merr)
-}
-
-func (m *Manager) initFirewall() (err error) {
 	workTable, err := m.createWorkTable()
 	if err != nil {
 		return fmt.Errorf("create work table: %w", err)
 	}
 
-	defer func() {
-		if err != nil {
-			m.rollbackInit()
-		}
-	}()
-
 	if err := m.router.init(workTable); err != nil {
 		return fmt.Errorf("router init: %w", err)
 	}
 
 	if err := m.aclManager.init(workTable); err != nil {
+		// TODO: cleanup router
 		return fmt.Errorf("acl manager init: %w", err)
 	}
 
-	if m.hasIPv6() {
-		if err := m.initIPv6(); err != nil {
-			// Peer has a v6 address: v6 firewall MUST work or we risk fail-open.
-			return fmt.Errorf("init IPv6 firewall (required because peer has IPv6 address): %w", err)
-		}
-	}
-
 	if err := m.initNoTrackChains(workTable); err != nil {
 		log.Warnf("raw priority chains not available, notrack rules will be disabled: %v", err)
 	}
 
-	return nil
-}
-
-// persistState saves the current interface state for potential recreation on restart.
-// Unlike iptables, which requires tracking individual rules, nftables maintains
-// a known state (our netbird table plus a few static rules). This allows for easy
-// cleanup using Close() without needing to store specific rules.
-func (m *Manager) persistState(stateManager *statemanager.Manager) {
 	stateManager.RegisterState(&ShutdownState{})
 
+	// We only need to record minimal interface state for potential recreation.
+	// Unlike iptables, which requires tracking individual rules, nftables maintains
+	// a known state (our netbird table plus a few static rules). This allows for easy
+	// cleanup using Close() without needing to store specific rules.
 	if err := stateManager.UpdateState(&ShutdownState{
 		InterfaceState: &InterfaceState{
 			NameStr:   m.wgIface.Name(),
@@ -226,29 +114,14 @@ func (m *Manager) persistState(stateManager *statemanager.Manager) {
 		log.Errorf("failed to update state: %v", err)
 	}
 
+	// persist early
 	go func() {
 		if err := stateManager.PersistState(context.Background()); err != nil {
 			log.Errorf("failed to persist state: %v", err)
 		}
 	}()
-}
 
-// rollbackInit performs best-effort cleanup of already-initialized state when Init fails partway through.
-func (m *Manager) rollbackInit() {
-	if err := m.router.Reset(); err != nil {
-		log.Warnf("rollback router: %v", err)
-	}
-	if m.hasIPv6() {
-		if err := m.router6.Reset(); err != nil {
-			log.Warnf("rollback v6 router: %v", err)
-		}
-	}
-	if err := m.cleanupNetbirdTables(); err != nil {
-		log.Warnf("cleanup tables: %v", err)
-	}
-	if err := m.rConn.Flush(); err != nil {
-		log.Warnf("flush: %v", err)
-	}
+	return nil
 }
 
 // AddPeerFiltering rule to the firewall
@@ -267,14 +140,12 @@ func (m *Manager) AddPeerFiltering(
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if ip.To4() != nil {
-		return m.aclManager.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
+	rawIP := ip.To4()
+	if rawIP == nil {
+		return nil, fmt.Errorf("unsupported IP version: %s", ip.String())
 	}
 
-	if !m.hasIPv6() {
-		return nil, fmt.Errorf("add peer filtering for %s: %w", ip, firewall.ErrIPv6NotInitialized)
-	}
-	return m.aclManager6.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
+	return m.aclManager.AddPeerFiltering(id, ip, proto, sPort, dPort, action, ipsetName)
 }
 
 func (m *Manager) AddRouteFiltering(
@@ -288,11 +159,8 @@ func (m *Manager) AddRouteFiltering(
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if isIPv6RouteRule(sources, destination) {
-		if !m.hasIPv6() {
-			return nil, fmt.Errorf("add route filtering: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
+	if destination.IsPrefix() && !destination.Prefix.Addr().Is4() {
+		return nil, fmt.Errorf("unsupported IP version: %s", destination.Prefix.Addr().String())
 	}
 
 	return m.router.AddRouteFiltering(id, sources, destination, proto, sPort, dPort, action)
@@ -303,66 +171,15 @@ func (m *Manager) DeletePeerRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if m.hasIPv6() && isIPv6Rule(rule) {
-		return m.aclManager6.DeletePeerRule(rule)
-	}
 	return m.aclManager.DeletePeerRule(rule)
 }
 
-func isIPv6Rule(rule firewall.Rule) bool {
-	r, ok := rule.(*Rule)
-	return ok && r.nftRule != nil && r.nftRule.Table != nil && r.nftRule.Table.Family == nftables.TableFamilyIPv6
-}
-
-// isIPv6RouteRule determines whether a route rule belongs to the v6 table.
-// For static routes, the destination prefix determines the family. For dynamic
-// routes (DomainSet), the sources determine the family since management
-// duplicates dynamic rules per family.
-func isIPv6RouteRule(sources []netip.Prefix, destination firewall.Network) bool {
-	if destination.IsPrefix() {
-		return destination.Prefix.Addr().Is6()
-	}
-	return len(sources) > 0 && sources[0].Addr().Is6()
-}
-
-// DeleteRouteRule deletes a routing rule. Route rules live in exactly one
-// router; the cached maps are normally authoritative, so the kernel is only
-// consulted when neither map knows about the rule.
+// DeleteRouteRule deletes a routing rule
 func (m *Manager) DeleteRouteRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	id := rule.ID()
-	r, err := m.routerForRuleID(id, (*router).hasRule)
-	if err != nil {
-		return err
-	}
-	return r.DeleteRouteRule(rule)
-}
-
-// routerForRuleID picks the router holding the rule with the given id, using
-// the supplied lookup. If the cached maps disagree (or both miss), it refreshes
-// from the kernel once and re-checks before falling back to the v4 router.
-func (m *Manager) routerForRuleID(id string, has func(*router, string) bool) (*router, error) {
-	if has(m.router, id) {
-		return m.router, nil
-	}
-	if m.hasIPv6() && has(m.router6, id) {
-		return m.router6, nil
-	}
-	if !m.hasIPv6() {
-		return m.router, nil
-	}
-	if err := m.router.refreshRulesMap(); err != nil {
-		return nil, fmt.Errorf("refresh v4 rules: %w", err)
-	}
-	if err := m.router6.refreshRulesMap(); err != nil {
-		return nil, fmt.Errorf("refresh v6 rules: %w", err)
-	}
-	if has(m.router6, id) && !has(m.router, id) {
-		return m.router6, nil
-	}
-	return m.router, nil
+	return m.router.DeleteRouteRule(rule)
 }
 
 func (m *Manager) IsServerRouteSupported() bool {
@@ -377,70 +194,19 @@ func (m *Manager) AddNatRule(pair firewall.RouterPair) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if pair.Destination.IsPrefix() && pair.Destination.Prefix.Addr().Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("add NAT rule: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddNatRule(pair)
-	}
-
-	if err := m.router.AddNatRule(pair); err != nil {
-		return err
-	}
-
-	// Dynamic routes need NAT in both tables since resolved IPs can be
-	// either v4 or v6. This covers both DomainSet (modern) and the legacy
-	// wildcard 0.0.0.0/0 destination where the client resolves DNS.
-	// On v6 failure we keep the v4 NAT rule rather than rolling back: half
-	// connectivity is better than none, and RemoveNatRule is content-keyed
-	// so the eventual cleanup still works.
-	if m.hasIPv6() && pair.Dynamic {
-		v6Pair := firewall.ToV6NatPair(pair)
-		if err := m.router6.AddNatRule(v6Pair); err != nil {
-			return fmt.Errorf("add v6 NAT rule: %w", err)
-		}
-	}
-
-	return nil
+	return m.router.AddNatRule(pair)
 }
 
 func (m *Manager) RemoveNatRule(pair firewall.RouterPair) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if pair.Destination.IsPrefix() && pair.Destination.Prefix.Addr().Is6() {
-		if !m.hasIPv6() {
-			return nil
-		}
-		return m.router6.RemoveNatRule(pair)
-	}
-
-	var merr *multierror.Error
-
-	if err := m.router.RemoveNatRule(pair); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("remove v4 NAT rule: %w", err))
-	}
-
-	if m.hasIPv6() && pair.Dynamic {
-		v6Pair := firewall.ToV6NatPair(pair)
-		if err := m.router6.RemoveNatRule(v6Pair); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("remove v6 NAT rule: %w", err))
-		}
-	}
-
-	return nberrors.FormatErrorOrNil(merr)
+	return m.router.RemoveNatRule(pair)
 }
 
 // AllowNetbird allows netbird interface traffic.
 // This is called when USPFilter wraps the native firewall, adding blanket accept
 // rules so that packet filtering is handled in userspace instead of by netfilter.
-//
-// TODO: In USP mode this only adds ACCEPT to the netbird table's own chains,
-// which doesn't override DROP rules in external tables (e.g. firewalld).
-// Should add passthrough rules to external chains (like the native mode router's
-// addExternalChainsRules does) for both the netbird table family and inet tables.
-// The netbird table itself is fine (routing chains already exist there), but
-// non-netbird tables with INPUT/FORWARD hooks can still DROP our WG traffic.
 func (m *Manager) AllowNetbird() error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
@@ -448,11 +214,6 @@ func (m *Manager) AllowNetbird() error {
 	if err := m.aclManager.createDefaultAllowRules(); err != nil {
 		return fmt.Errorf("create default allow rules: %w", err)
 	}
-	if m.hasIPv6() {
-		if err := m.aclManager6.createDefaultAllowRules(); err != nil {
-			return fmt.Errorf("create v6 default allow rules: %w", err)
-		}
-	}
 	if err := m.rConn.Flush(); err != nil {
 		return fmt.Errorf("flush allow input netbird rules: %w", err)
 	}
@@ -466,47 +227,31 @@ func (m *Manager) AllowNetbird() error {
 
 // SetLegacyManagement sets the route manager to use legacy management
 func (m *Manager) SetLegacyManagement(isLegacy bool) error {
-	if err := firewall.SetLegacyManagement(m.router, isLegacy); err != nil {
-		return err
-	}
-	if m.hasIPv6() {
-		return firewall.SetLegacyManagement(m.router6, isLegacy)
-	}
-	return nil
+	return firewall.SetLegacyManagement(m.router, isLegacy)
 }
 
 // Close closes the firewall manager
 func (m *Manager) Close(stateManager *statemanager.Manager) error {
-	m.extMonitor.stop()
-
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	var merr *multierror.Error
-
 	if err := m.router.Reset(); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("reset router: %v", err))
-	}
-
-	if m.hasIPv6() {
-		if err := m.router6.Reset(); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("reset v6 router: %v", err))
-		}
+		return fmt.Errorf("reset router: %v", err)
 	}
 
 	if err := m.cleanupNetbirdTables(); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("cleanup netbird tables: %v", err))
+		return fmt.Errorf("cleanup netbird tables: %v", err)
 	}
 
 	if err := m.rConn.Flush(); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf(flushError, err))
+		return fmt.Errorf(flushError, err)
 	}
 
 	if err := stateManager.DeleteState(&ShutdownState{}); err != nil {
-		merr = multierror.Append(merr, fmt.Errorf("delete state: %v", err))
+		return fmt.Errorf("delete state: %v", err)
 	}
 
-	return nberrors.FormatErrorOrNil(merr)
+	return nil
 }
 
 func (m *Manager) cleanupNetbirdTables() error {
@@ -555,12 +300,6 @@ func (m *Manager) Flush() error {
 		return err
 	}
 
-	if m.hasIPv6() {
-		if err := m.aclManager6.Flush(); err != nil {
-			return fmt.Errorf("flush v6 acl: %w", err)
-		}
-	}
-
 	if err := m.refreshNoTrackChains(); err != nil {
 		log.Errorf("failed to refresh notrack chains: %v", err)
 	}
@@ -573,12 +312,6 @@ func (m *Manager) AddDNATRule(rule firewall.ForwardRule) (firewall.Rule, error)
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if rule.TranslatedAddress.Is6() {
-		if !m.hasIPv6() {
-			return nil, fmt.Errorf("add DNAT rule: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddDNATRule(rule)
-	}
 	return m.router.AddDNATRule(rule)
 }
 
@@ -587,11 +320,7 @@ func (m *Manager) DeleteDNATRule(rule firewall.Rule) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	r, err := m.routerForRuleID(rule.ID(), (*router).hasDNATRule)
-	if err != nil {
-		return err
-	}
-	return r.DeleteDNATRule(rule)
+	return m.router.DeleteDNATRule(rule)
 }
 
 // UpdateSet updates the set with the given prefixes
@@ -599,82 +328,39 @@ func (m *Manager) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	var v4Prefixes, v6Prefixes []netip.Prefix
-	for _, p := range prefixes {
-		if p.Addr().Is6() {
-			v6Prefixes = append(v6Prefixes, p)
-		} else {
-			v4Prefixes = append(v4Prefixes, p)
-		}
-	}
-
-	if err := m.router.UpdateSet(set, v4Prefixes); err != nil {
-		return err
-	}
-
-	if m.hasIPv6() && len(v6Prefixes) > 0 {
-		if err := m.router6.UpdateSet(set, v6Prefixes); err != nil {
-			return fmt.Errorf("update v6 set: %w", err)
-		}
-	}
-
-	return nil
+	return m.router.UpdateSet(set, prefixes)
 }
 
 // AddInboundDNAT adds an inbound DNAT rule redirecting traffic from NetBird peers to local services.
-func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if localAddr.Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("add inbound DNAT: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
-	}
-	return m.router.AddInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.router.AddInboundDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 // RemoveInboundDNAT removes an inbound DNAT rule.
-func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if localAddr.Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("remove inbound DNAT: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
-	}
-	return m.router.RemoveInboundDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.router.RemoveInboundDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 // AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
-func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if localAddr.Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("add output DNAT: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
-	}
-	return m.router.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.router.AddOutputDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 // RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
-func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	if localAddr.Is6() {
-		if !m.hasIPv6() {
-			return fmt.Errorf("remove output DNAT: %w", firewall.ErrIPv6NotInitialized)
-		}
-		return m.router6.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
-	}
-	return m.router.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.router.RemoveOutputDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 const (
@@ -848,11 +534,7 @@ func (m *Manager) refreshNoTrackChains() error {
 }
 
 func (m *Manager) createWorkTable() (*nftables.Table, error) {
-	return m.createWorkTableFamily(nftables.TableFamilyIPv4)
-}
-
-func (m *Manager) createWorkTableFamily(family nftables.TableFamily) (*nftables.Table, error) {
-	tables, err := m.rConn.ListTablesOfFamily(family)
+	tables, err := m.rConn.ListTablesOfFamily(nftables.TableFamilyIPv4)
 	if err != nil {
 		return nil, fmt.Errorf("list of tables: %w", err)
 	}
@@ -864,7 +546,7 @@ func (m *Manager) createWorkTableFamily(family nftables.TableFamily) (*nftables.
 		}
 	}
 
-	table := m.rConn.AddTable(&nftables.Table{Name: tableName, Family: family})
+	table := m.rConn.AddTable(&nftables.Table{Name: getTableName(), Family: nftables.TableFamilyIPv4})
 	err = m.rConn.Flush()
 	return table, err
 }

client/firewall/nftables/manager_linux_test.go

@@ -383,138 +383,10 @@ func TestNftablesManagerCompatibilityWithIptables(t *testing.T) {
 	err = manager.AddNatRule(pair)
 	require.NoError(t, err, "failed to add NAT rule")
 
-	dnatRule, err := manager.AddDNATRule(fw.ForwardRule{
-		Protocol:          fw.ProtocolTCP,
-		DestinationPort:   fw.Port{Values: []uint16{8080}},
-		TranslatedAddress: netip.MustParseAddr("100.96.0.2"),
-		TranslatedPort:    fw.Port{Values: []uint16{80}},
-	})
-	require.NoError(t, err, "failed to add DNAT rule")
-
-	t.Cleanup(func() {
-		require.NoError(t, manager.DeleteDNATRule(dnatRule), "failed to delete DNAT rule")
-	})
-
 	stdout, stderr = runIptablesSave(t)
 	verifyIptablesOutput(t, stdout, stderr)
 }
 
-func TestNftablesManagerIPv6CompatibilityWithIp6tables(t *testing.T) {
-	if check() != NFTABLES {
-		t.Skip("nftables not supported on this system")
-	}
-
-	for _, bin := range []string{"ip6tables", "ip6tables-save", "iptables-save"} {
-		if _, err := exec.LookPath(bin); err != nil {
-			t.Skipf("%s not available on this system: %v", bin, err)
-		}
-	}
-
-	// Seed ip6 tables in the nft backend. Docker may not create them.
-	seedIp6tables(t)
-
-	ifaceMockV6 := &iFaceMock{
-		NameFunc: func() string { return "wt-test" },
-		AddressFunc: func() wgaddr.Address {
-			return wgaddr.Address{
-				IP:      netip.MustParseAddr("100.96.0.1"),
-				Network: netip.MustParsePrefix("100.96.0.0/16"),
-				IPv6:    netip.MustParseAddr("fd00::1"),
-				IPv6Net: netip.MustParsePrefix("fd00::/64"),
-			}
-		},
-	}
-
-	manager, err := Create(ifaceMockV6, iface.DefaultMTU)
-	require.NoError(t, err, "create manager")
-	require.NoError(t, manager.Init(nil))
-
-	t.Cleanup(func() {
-		require.NoError(t, manager.Close(nil), "close manager")
-
-		stdout, stderr := runIp6tablesSave(t)
-		verifyIp6tablesOutput(t, stdout, stderr)
-	})
-
-	ip := netip.MustParseAddr("fd00::2")
-	_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept, "")
-	require.NoError(t, err, "add v6 peer filtering rule")
-
-	_, err = manager.AddRouteFiltering(
-		nil,
-		[]netip.Prefix{netip.MustParsePrefix("fd00:1::/64")},
-		fw.Network{Prefix: netip.MustParsePrefix("2001:db8::/48")},
-		fw.ProtocolTCP,
-		nil,
-		&fw.Port{Values: []uint16{443}},
-		fw.ActionAccept,
-	)
-	require.NoError(t, err, "add v6 route filtering rule")
-
-	err = manager.AddNatRule(fw.RouterPair{
-		Source:      fw.Network{Prefix: netip.MustParsePrefix("fd00::/64")},
-		Destination: fw.Network{Prefix: netip.MustParsePrefix("2001:db8::/48")},
-		Masquerade:  true,
-	})
-	require.NoError(t, err, "add v6 NAT rule")
-
-	dnatRule, err := manager.AddDNATRule(fw.ForwardRule{
-		Protocol:          fw.ProtocolTCP,
-		DestinationPort:   fw.Port{Values: []uint16{8080}},
-		TranslatedAddress: netip.MustParseAddr("fd00::2"),
-		TranslatedPort:    fw.Port{Values: []uint16{80}},
-	})
-	require.NoError(t, err, "add v6 DNAT rule")
-
-	t.Cleanup(func() {
-		require.NoError(t, manager.DeleteDNATRule(dnatRule), "delete v6 DNAT rule")
-	})
-
-	stdout, stderr := runIptablesSave(t)
-	verifyIptablesOutput(t, stdout, stderr)
-
-	stdout, stderr = runIp6tablesSave(t)
-	verifyIp6tablesOutput(t, stdout, stderr)
-}
-
-func seedIp6tables(t *testing.T) {
-	t.Helper()
-	for _, tc := range []struct{ table, chain string }{
-		{"filter", "FORWARD"},
-		{"nat", "POSTROUTING"},
-		{"mangle", "FORWARD"},
-	} {
-		add := exec.Command("ip6tables", "-t", tc.table, "-A", tc.chain, "-j", "ACCEPT")
-		require.NoError(t, add.Run(), "seed ip6tables -t %s", tc.table)
-		del := exec.Command("ip6tables", "-t", tc.table, "-D", tc.chain, "-j", "ACCEPT")
-		require.NoError(t, del.Run(), "unseed ip6tables -t %s", tc.table)
-	}
-}
-
-func runIp6tablesSave(t *testing.T) (string, string) {
-	t.Helper()
-	var stdout, stderr bytes.Buffer
-	cmd := exec.Command("ip6tables-save")
-	cmd.Stdout = &stdout
-	cmd.Stderr = &stderr
-	require.NoError(t, cmd.Run(), "ip6tables-save failed")
-	return stdout.String(), stderr.String()
-}
-
-func verifyIp6tablesOutput(t *testing.T, stdout, stderr string) {
-	t.Helper()
-	for _, msg := range []string{
-		"Table `nat' is incompatible",
-		"Table `mangle' is incompatible",
-		"Table `filter' is incompatible",
-	} {
-		require.NotContains(t, stdout, msg,
-			"ip6tables-save stdout reports incompatibility: %s", stdout)
-		require.NotContains(t, stderr, msg,
-			"ip6tables-save stderr reports incompatibility: %s", stderr)
-	}
-}
-
 func TestNftablesManagerCompatibilityWithIptablesFor6kPrefixes(t *testing.T) {
 	if check() != NFTABLES {
 		t.Skip("nftables not supported on this system")

client/firewall/nftables/router_linux.go

@@ -50,10 +50,8 @@ const (
 	dnatSuffix = "_dnat"
 	snatSuffix = "_snat"
 
-	// ipv4TCPHeaderSize is the minimum IPv4 (20) + TCP (20) header size for MSS calculation.
-	ipv4TCPHeaderSize = 40
-	// ipv6TCPHeaderSize is the minimum IPv6 (40) + TCP (20) header size for MSS calculation.
-	ipv6TCPHeaderSize = 60
+	// ipTCPHeaderMinSize represents minimum IP (20) + TCP (20) header size for MSS calculation
+	ipTCPHeaderMinSize = 40
 
 	// maxPrefixesSet 1638 prefixes start to fail, taking some margin
 	maxPrefixesSet       = 1500
@@ -78,7 +76,6 @@ type router struct {
 	rules        map[string]*nftables.Rule
 	ipsetCounter *refcounter.Counter[string, setInput, *nftables.Set]
 
-	af               addrFamily
 	wgIface          iFaceMapper
 	ipFwdState       *ipfwdstate.IPForwardingState
 	legacyManagement bool
@@ -91,7 +88,6 @@ func newRouter(workTable *nftables.Table, wgIface iFaceMapper, mtu uint16) (*rou
 		workTable:  workTable,
 		chains:     make(map[string]*nftables.Chain),
 		rules:      make(map[string]*nftables.Rule),
-		af:         familyForAddr(workTable.Family == nftables.TableFamilyIPv4),
 		wgIface:    wgIface,
 		ipFwdState: ipfwdstate.NewIPForwardingState(),
 		mtu:        mtu,
@@ -154,7 +150,7 @@ func (r *router) Reset() error {
 func (r *router) removeNatPreroutingRules() error {
 	table := &nftables.Table{
 		Name:   tableNat,
-		Family: r.af.tableFamily,
+		Family: nftables.TableFamilyIPv4,
 	}
 	chain := &nftables.Chain{
 		Name:     chainNameNatPrerouting,
@@ -187,7 +183,7 @@ func (r *router) removeNatPreroutingRules() error {
 }
 
 func (r *router) loadFilterTable() (*nftables.Table, error) {
-	tables, err := r.conn.ListTablesOfFamily(r.af.tableFamily)
+	tables, err := r.conn.ListTablesOfFamily(nftables.TableFamilyIPv4)
 	if err != nil {
 		return nil, fmt.Errorf("list tables: %w", err)
 	}
@@ -423,7 +419,7 @@ func (r *router) AddRouteFiltering(
 
 	// Handle protocol
 	if proto != firewall.ProtocolALL {
-		protoNum, err := r.af.protoNum(proto)
+		protoNum, err := protoToInt(proto)
 		if err != nil {
 			return nil, fmt.Errorf("convert protocol to number: %w", err)
 		}
@@ -483,24 +479,7 @@ func (r *router) getIpSet(set firewall.Set, prefixes []netip.Prefix, isSource bo
 		return nil, fmt.Errorf("create or get ipset: %w", err)
 	}
 
-	return r.getIpSetExprs(ref, isSource)
-}
-
-func (r *router) iptablesProto() iptables.Protocol {
-	if r.af.tableFamily == nftables.TableFamilyIPv6 {
-		return iptables.ProtocolIPv6
-	}
-	return iptables.ProtocolIPv4
-}
-
-func (r *router) hasRule(id string) bool {
-	_, ok := r.rules[id]
-	return ok
-}
-
-func (r *router) hasDNATRule(id string) bool {
-	_, ok := r.rules[id+dnatSuffix]
-	return ok
+	return getIpSetExprs(ref, isSource)
 }
 
 func (r *router) DeleteRouteRule(rule firewall.Rule) error {
@@ -549,10 +528,10 @@ func (r *router) createIpSet(setName string, input setInput) (*nftables.Set, err
 		Table:   r.workTable,
 		// required for prefixes
 		Interval: true,
-		KeyType:  r.af.setKeyType,
+		KeyType:  nftables.TypeIPAddr,
 	}
 
-	elements := r.convertPrefixesToSet(prefixes)
+	elements := convertPrefixesToSet(prefixes)
 	nElements := len(elements)
 
 	maxElements := maxPrefixesSet * 2
@@ -585,17 +564,23 @@ func (r *router) createIpSet(setName string, input setInput) (*nftables.Set, err
 	return nfset, nil
 }
 
-func (r *router) convertPrefixesToSet(prefixes []netip.Prefix) []nftables.SetElement {
+func convertPrefixesToSet(prefixes []netip.Prefix) []nftables.SetElement {
 	var elements []nftables.SetElement
 	for _, prefix := range prefixes {
+		// TODO: Implement IPv6 support
+		if prefix.Addr().Is6() {
+			log.Tracef("skipping IPv6 prefix %s: IPv6 support not yet implemented", prefix)
+			continue
+		}
+
 		// nftables needs half-open intervals [firstIP, lastIP) for prefixes
 		// e.g. 10.0.0.0/24 becomes [10.0.0.0, 10.0.1.0), 10.1.1.1/32 becomes [10.1.1.1, 10.1.1.2) etc
 		firstIP := prefix.Addr()
 		lastIP := calculateLastIP(prefix).Next()
 
 		elements = append(elements,
-			// the nft tool also adds a zero-address IntervalEnd element, see https://github.com/google/nftables/issues/247
-			// nftables.SetElement{Key: make([]byte, r.af.addrLen), IntervalEnd: true},
+			// the nft tool also adds a line like this, see https://github.com/google/nftables/issues/247
+			// nftables.SetElement{Key: []byte{0, 0, 0, 0}, IntervalEnd: true},
 			nftables.SetElement{Key: firstIP.AsSlice()},
 			nftables.SetElement{Key: lastIP.AsSlice(), IntervalEnd: true},
 		)
@@ -605,20 +590,10 @@ func (r *router) convertPrefixesToSet(prefixes []netip.Prefix) []nftables.SetEle
 
 // calculateLastIP determines the last IP in a given prefix.
 func calculateLastIP(prefix netip.Prefix) netip.Addr {
-	masked := prefix.Masked()
-	if masked.Addr().Is4() {
-		hostMask := ^uint32(0) >> masked.Bits()
-		lastIP := uint32FromNetipAddr(masked.Addr()) | hostMask
-		return netip.AddrFrom4(uint32ToBytes(lastIP))
-	}
+	hostMask := ^uint32(0) >> prefix.Masked().Bits()
+	lastIP := uint32FromNetipAddr(prefix.Addr()) | hostMask
 
-	// IPv6: set host bits to all 1s
-	b := masked.Addr().As16()
-	bits := masked.Bits()
-	for i := bits; i < 128; i++ {
-		b[i/8] |= 1 << (7 - i%8)
-	}
-	return netip.AddrFrom16(b)
+	return netip.AddrFrom4(uint32ToBytes(lastIP))
 }
 
 // Utility function to convert netip.Addr to uint32.
@@ -870,16 +845,9 @@ func (r *router) addPostroutingRules() {
 }
 
 // addMSSClampingRules adds MSS clamping rules to prevent fragmentation for forwarded traffic.
+// TODO: Add IPv6 support
 func (r *router) addMSSClampingRules() error {
-	overhead := uint16(ipv4TCPHeaderSize)
-	if r.af.tableFamily == nftables.TableFamilyIPv6 {
-		overhead = ipv6TCPHeaderSize
-	}
-	if r.mtu <= overhead {
-		log.Debugf("MTU %d too small for MSS clamping (overhead %d), skipping", r.mtu, overhead)
-		return nil
-	}
-	mss := r.mtu - overhead
+	mss := r.mtu - ipTCPHeaderMinSize
 
 	exprsOut := []expr.Any{
 		&expr.Meta{
@@ -1086,22 +1054,17 @@ func (r *router) acceptFilterTableRules() error {
 		log.Debugf("Used %s to add accept forward and input rules", fw)
 	}()
 
-	// Try iptables first and fallback to nftables if iptables is not available.
-	// Use the correct protocol (iptables vs ip6tables) for the address family.
-	ipt, err := iptables.NewWithProtocol(r.iptablesProto())
+	// Try iptables first and fallback to nftables if iptables is not available
+	ipt, err := iptables.New()
 	if err != nil {
+		// iptables is not available but the filter table exists
 		log.Warnf("Will use nftables to manipulate the filter table because iptables is not available: %v", err)
 
 		fw = "nftables"
 		return r.acceptFilterRulesNftables(r.filterTable)
 	}
 
-	if err := r.acceptFilterRulesIptables(ipt); err != nil {
-		log.Warnf("iptables failed (table may be incompatible), falling back to nftables: %v", err)
-		fw = "nftables"
-		return r.acceptFilterRulesNftables(r.filterTable)
-	}
-	return nil
+	return r.acceptFilterRulesIptables(ipt)
 }
 
 func (r *router) acceptFilterRulesIptables(ipt *iptables.IPTables) error {
@@ -1172,122 +1135,83 @@ func (r *router) acceptExternalChainsRules() error {
 	}
 
 	intf := ifname(r.wgIface.Name())
+
 	for _, chain := range chains {
-		r.applyExternalChainAccept(chain, intf)
+		if chain.Hooknum == nil {
+			log.Debugf("skipping external chain %s/%s: hooknum is nil", chain.Table.Name, chain.Name)
+			continue
+		}
+
+		log.Debugf("adding accept rules to external %s chain: %s %s/%s",
+			hookName(chain.Hooknum), familyName(chain.Table.Family), chain.Table.Name, chain.Name)
+
+		switch *chain.Hooknum {
+		case *nftables.ChainHookForward:
+			r.insertForwardAcceptRules(chain, intf)
+		case *nftables.ChainHookInput:
+			r.insertInputAcceptRule(chain, intf)
+		}
 	}
 
 	if err := r.conn.Flush(); err != nil {
 		return fmt.Errorf("flush external chain rules: %w", err)
 	}
+
 	return nil
 }
 
-func (r *router) applyExternalChainAccept(chain *nftables.Chain, intf []byte) {
-	if chain.Hooknum == nil {
-		log.Debugf("skipping external chain %s/%s: hooknum is nil", chain.Table.Name, chain.Name)
-		return
-	}
-
-	log.Debugf("adding accept rules to external %s chain: %s %s/%s",
-		hookName(chain.Hooknum), familyName(chain.Table.Family), chain.Table.Name, chain.Name)
-
-	switch *chain.Hooknum {
-	case *nftables.ChainHookForward:
-		r.insertForwardAcceptRules(chain, intf)
-	case *nftables.ChainHookInput:
-		r.insertInputAcceptRule(chain, intf)
-	}
-}
-
 func (r *router) insertForwardAcceptRules(chain *nftables.Chain, intf []byte) {
-	existing, err := r.existingNetbirdRulesInChain(chain)
-	if err != nil {
-		log.Warnf("skip forward accept rules in %s/%s: %v", chain.Table.Name, chain.Name, err)
-		return
-	}
-	r.insertForwardIifRule(chain, intf, existing)
-	r.insertForwardOifEstablishedRule(chain, intf, existing)
-}
-
-func (r *router) insertForwardIifRule(chain *nftables.Chain, intf []byte, existing map[string]bool) {
-	if existing[userDataAcceptForwardRuleIif] {
-		return
-	}
-	r.conn.InsertRule(&nftables.Rule{
+	iifRule := &nftables.Rule{
 		Table: chain.Table,
 		Chain: chain,
 		Exprs: []expr.Any{
 			&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
-			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: intf},
+			&expr.Cmp{
+				Op:       expr.CmpOpEq,
+				Register: 1,
+				Data:     intf,
+			},
 			&expr.Counter{},
 			&expr.Verdict{Kind: expr.VerdictAccept},
 		},
 		UserData: []byte(userDataAcceptForwardRuleIif),
-	})
-}
+	}
+	r.conn.InsertRule(iifRule)
 
-func (r *router) insertForwardOifEstablishedRule(chain *nftables.Chain, intf []byte, existing map[string]bool) {
-	if existing[userDataAcceptForwardRuleOif] {
-		return
-	}
-	exprs := []expr.Any{
+	oifExprs := []expr.Any{
 		&expr.Meta{Key: expr.MetaKeyOIFNAME, Register: 1},
-		&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: intf},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     intf,
+		},
 	}
-	r.conn.InsertRule(&nftables.Rule{
+	oifRule := &nftables.Rule{
 		Table:    chain.Table,
 		Chain:    chain,
-		Exprs:    append(exprs, getEstablishedExprs(2)...),
+		Exprs:    append(oifExprs, getEstablishedExprs(2)...),
 		UserData: []byte(userDataAcceptForwardRuleOif),
-	})
+	}
+	r.conn.InsertRule(oifRule)
 }
 
 func (r *router) insertInputAcceptRule(chain *nftables.Chain, intf []byte) {
-	existing, err := r.existingNetbirdRulesInChain(chain)
-	if err != nil {
-		log.Warnf("skip input accept rule in %s/%s: %v", chain.Table.Name, chain.Name, err)
-		return
-	}
-	if existing[userDataAcceptInputRule] {
-		return
-	}
-	r.conn.InsertRule(&nftables.Rule{
+	inputRule := &nftables.Rule{
 		Table: chain.Table,
 		Chain: chain,
 		Exprs: []expr.Any{
 			&expr.Meta{Key: expr.MetaKeyIIFNAME, Register: 1},
-			&expr.Cmp{Op: expr.CmpOpEq, Register: 1, Data: intf},
+			&expr.Cmp{
+				Op:       expr.CmpOpEq,
+				Register: 1,
+				Data:     intf,
+			},
 			&expr.Counter{},
 			&expr.Verdict{Kind: expr.VerdictAccept},
 		},
 		UserData: []byte(userDataAcceptInputRule),
-	})
-}
-
-// existingNetbirdRulesInChain returns the set of netbird-owned UserData tags present in a chain; callers must bail on error since InsertRule is additive.
-func (r *router) existingNetbirdRulesInChain(chain *nftables.Chain) (map[string]bool, error) {
-	rules, err := r.conn.GetRules(chain.Table, chain)
-	if err != nil {
-		return nil, fmt.Errorf("list rules: %w", err)
 	}
-	present := map[string]bool{}
-	for _, rule := range rules {
-		if !isNetbirdAcceptRuleTag(rule.UserData) {
-			continue
-		}
-		present[string(rule.UserData)] = true
-	}
-	return present, nil
-}
-
-func isNetbirdAcceptRuleTag(userData []byte) bool {
-	switch string(userData) {
-	case userDataAcceptForwardRuleIif,
-		userDataAcceptForwardRuleOif,
-		userDataAcceptInputRule:
-		return true
-	}
-	return false
+	r.conn.InsertRule(inputRule)
 }
 
 func (r *router) removeAcceptFilterRules() error {
@@ -1309,17 +1233,13 @@ func (r *router) removeFilterTableRules() error {
 		return nil
 	}
 
-	ipt, err := iptables.NewWithProtocol(r.iptablesProto())
+	ipt, err := iptables.New()
 	if err != nil {
 		log.Debugf("iptables not available, using nftables to remove filter rules: %v", err)
 		return r.removeAcceptRulesFromTable(r.filterTable)
 	}
 
-	if err := r.removeAcceptFilterRulesIptables(ipt); err != nil {
-		log.Debugf("iptables removal failed (table may be incompatible), falling back to nftables: %v", err)
-		return r.removeAcceptRulesFromTable(r.filterTable)
-	}
-	return nil
+	return r.removeAcceptFilterRulesIptables(ipt)
 }
 
 func (r *router) removeAcceptRulesFromTable(table *nftables.Table) error {
@@ -1386,7 +1306,7 @@ func (r *router) removeExternalChainsRules() error {
 func (r *router) findExternalChains() []*nftables.Chain {
 	var chains []*nftables.Chain
 
-	families := []nftables.TableFamily{r.af.tableFamily, nftables.TableFamilyINet}
+	families := []nftables.TableFamily{nftables.TableFamilyIPv4, nftables.TableFamilyINet}
 
 	for _, family := range families {
 		allChains, err := r.conn.ListChainsOfTableFamily(family)
@@ -1417,8 +1337,8 @@ func (r *router) isExternalChain(chain *nftables.Chain) bool {
 		return false
 	}
 
-	// Skip iptables/ip6tables-managed tables (adding nft-native rules breaks iptables-save compat)
-	if (chain.Table.Family == nftables.TableFamilyIPv4 || chain.Table.Family == nftables.TableFamilyIPv6) && isIptablesTable(chain.Table.Name) {
+	// Skip all iptables-managed tables in the ip family
+	if chain.Table.Family == nftables.TableFamilyIPv4 && isIptablesTable(chain.Table.Name) {
 		return false
 	}
 
@@ -1559,7 +1479,7 @@ func (r *router) AddDNATRule(rule firewall.ForwardRule) (firewall.Rule, error) {
 		return rule, nil
 	}
 
-	protoNum, err := r.af.protoNum(rule.Protocol)
+	protoNum, err := protoToInt(rule.Protocol)
 	if err != nil {
 		return nil, fmt.Errorf("convert protocol to number: %w", err)
 	}
@@ -1622,7 +1542,7 @@ func (r *router) addDnatRedirect(rule firewall.ForwardRule, protoNum uint8, rule
 	dnatExprs = append(dnatExprs,
 		&expr.NAT{
 			Type:        expr.NATTypeDestNAT,
-			Family:      uint32(r.af.tableFamily),
+			Family:      uint32(nftables.TableFamilyIPv4),
 			RegAddrMin:  1,
 			RegProtoMin: regProtoMin,
 			RegProtoMax: regProtoMax,
@@ -1715,15 +1635,14 @@ func (r *router) addXTablesRedirect(dnatExprs []expr.Any, ruleKey string, rule f
 		},
 	)
 
-	natTable := &nftables.Table{
-		Name:   tableNat,
-		Family: r.af.tableFamily,
-	}
 	dnatRule := &nftables.Rule{
-		Table: natTable,
+		Table: &nftables.Table{
+			Name:   tableNat,
+			Family: nftables.TableFamilyIPv4,
+		},
 		Chain: &nftables.Chain{
 			Name:     chainNameNatPrerouting,
-			Table:    natTable,
+			Table:    r.filterTable,
 			Type:     nftables.ChainTypeNAT,
 			Hooknum:  nftables.ChainHookPrerouting,
 			Priority: nftables.ChainPriorityNATDest,
@@ -1754,8 +1673,8 @@ func (r *router) addDnatMasq(rule firewall.ForwardRule, protoNum uint8, ruleKey
 		&expr.Payload{
 			DestRegister: 1,
 			Base:         expr.PayloadBaseNetworkHeader,
-			Offset:       r.af.dstAddrOffset,
-			Len:          r.af.addrLen,
+			Offset:       16,
+			Len:          4,
 		},
 		&expr.Cmp{
 			Op:       expr.CmpOpEq,
@@ -1833,7 +1752,7 @@ func (r *router) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
 		return fmt.Errorf("get set %s: %w", set.HashedName(), err)
 	}
 
-	elements := r.convertPrefixesToSet(prefixes)
+	elements := convertPrefixesToSet(prefixes)
 	if err := r.conn.SetAddElements(nfset, elements); err != nil {
 		return fmt.Errorf("add elements to set %s: %w", set.HashedName(), err)
 	}
@@ -1848,14 +1767,14 @@ func (r *router) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
 }
 
 // AddInboundDNAT adds an inbound DNAT rule redirecting traffic from NetBird peers to local services.
-func (r *router) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
-	ruleID := fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort)
+func (r *router) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	ruleID := fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
 
 	if _, exists := r.rules[ruleID]; exists {
 		return nil
 	}
 
-	protoNum, err := r.af.protoNum(protocol)
+	protoNum, err := protoToInt(protocol)
 	if err != nil {
 		return fmt.Errorf("convert protocol to number: %w", err)
 	}
@@ -1882,15 +1801,11 @@ func (r *router) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol
 		&expr.Cmp{
 			Op:       expr.CmpOpEq,
 			Register: 3,
-			Data:     binaryutil.BigEndian.PutUint16(originalPort),
+			Data:     binaryutil.BigEndian.PutUint16(sourcePort),
 		},
 	}
 
-	bits := 32
-	if localAddr.Is6() {
-		bits = 128
-	}
-	exprs = append(exprs, r.applyPrefix(netip.PrefixFrom(localAddr, bits), false)...)
+	exprs = append(exprs, applyPrefix(netip.PrefixFrom(localAddr, 32), false)...)
 
 	exprs = append(exprs,
 		&expr.Immediate{
@@ -1899,11 +1814,11 @@ func (r *router) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol
 		},
 		&expr.Immediate{
 			Register: 2,
-			Data:     binaryutil.BigEndian.PutUint16(translatedPort),
+			Data:     binaryutil.BigEndian.PutUint16(targetPort),
 		},
 		&expr.NAT{
 			Type:        expr.NATTypeDestNAT,
-			Family:      uint32(r.af.tableFamily),
+			Family:      uint32(nftables.TableFamilyIPv4),
 			RegAddrMin:  1,
 			RegProtoMin: 2,
 			RegProtoMax: 0,
@@ -1928,12 +1843,12 @@ func (r *router) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol
 }
 
 // RemoveInboundDNAT removes an inbound DNAT rule.
-func (r *router) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (r *router) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	if err := r.refreshRulesMap(); err != nil {
 		return fmt.Errorf(refreshRulesMapError, err)
 	}
 
-	ruleID := fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort)
+	ruleID := fmt.Sprintf("inbound-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
 
 	rule, exists := r.rules[ruleID]
 	if !exists {
@@ -1979,8 +1894,8 @@ func (r *router) ensureNATOutputChain() error {
 }
 
 // AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
-func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
-	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort)
+func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
 
 	if _, exists := r.rules[ruleID]; exists {
 		return nil
@@ -1990,7 +1905,7 @@ func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol,
 		return err
 	}
 
-	protoNum, err := r.af.protoNum(protocol)
+	protoNum, err := protoToInt(protocol)
 	if err != nil {
 		return fmt.Errorf("convert protocol to number: %w", err)
 	}
@@ -2011,15 +1926,11 @@ func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol,
 		&expr.Cmp{
 			Op:       expr.CmpOpEq,
 			Register: 2,
-			Data:     binaryutil.BigEndian.PutUint16(originalPort),
+			Data:     binaryutil.BigEndian.PutUint16(sourcePort),
 		},
 	}
 
-	bits := 32
-	if localAddr.Is6() {
-		bits = 128
-	}
-	exprs = append(exprs, r.applyPrefix(netip.PrefixFrom(localAddr, bits), false)...)
+	exprs = append(exprs, applyPrefix(netip.PrefixFrom(localAddr, 32), false)...)
 
 	exprs = append(exprs,
 		&expr.Immediate{
@@ -2028,11 +1939,11 @@ func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol,
 		},
 		&expr.Immediate{
 			Register: 2,
-			Data:     binaryutil.BigEndian.PutUint16(translatedPort),
+			Data:     binaryutil.BigEndian.PutUint16(targetPort),
 		},
 		&expr.NAT{
 			Type:        expr.NATTypeDestNAT,
-			Family:      uint32(r.af.tableFamily),
+			Family:      uint32(nftables.TableFamilyIPv4),
 			RegAddrMin:  1,
 			RegProtoMin: 2,
 		},
@@ -2056,12 +1967,12 @@ func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol,
 }
 
 // RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
-func (r *router) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (r *router) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	if err := r.refreshRulesMap(); err != nil {
 		return fmt.Errorf(refreshRulesMapError, err)
 	}
 
-	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort)
+	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
 
 	rule, exists := r.rules[ruleID]
 	if !exists {
@@ -2100,44 +2011,45 @@ func (r *router) applyNetwork(
 	}
 
 	if network.IsPrefix() {
-		return r.applyPrefix(network.Prefix, isSource), nil
+		return applyPrefix(network.Prefix, isSource), nil
 	}
 
 	return nil, nil
 }
 
 // applyPrefix generates nftables expressions for a CIDR prefix
-func (r *router) applyPrefix(prefix netip.Prefix, isSource bool) []expr.Any {
-	// dst offset by default
-	offset := r.af.dstAddrOffset
+func applyPrefix(prefix netip.Prefix, isSource bool) []expr.Any {
+	// dst offset
+	offset := uint32(16)
 	if isSource {
 		// src offset
-		offset = r.af.srcAddrOffset
+		offset = 12
 	}
 
 	ones := prefix.Bits()
-	// unspecified address (/0) doesn't need extra expressions
+	// 0.0.0.0/0 doesn't need extra expressions
 	if ones == 0 {
 		return nil
 	}
 
-	mask := net.CIDRMask(ones, r.af.totalBits)
-	xor := make([]byte, r.af.addrLen)
+	mask := net.CIDRMask(ones, 32)
 
 	return []expr.Any{
 		&expr.Payload{
 			DestRegister: 1,
 			Base:         expr.PayloadBaseNetworkHeader,
 			Offset:       offset,
-			Len:          r.af.addrLen,
+			Len:          4,
 		},
+		// netmask
 		&expr.Bitwise{
 			DestRegister:   1,
 			SourceRegister: 1,
-			Len:            r.af.addrLen,
+			Len:            4,
 			Mask:           mask,
-			Xor:            xor,
+			Xor:            []byte{0, 0, 0, 0},
 		},
+		// net address
 		&expr.Cmp{
 			Op:       expr.CmpOpEq,
 			Register: 1,
@@ -2220,12 +2132,13 @@ func getCtNewExprs() []expr.Any {
 	}
 }
 
-func (r *router) getIpSetExprs(ref refcounter.Ref[*nftables.Set], isSource bool) ([]expr.Any, error) {
-	// dst offset by default
-	offset := r.af.dstAddrOffset
+func getIpSetExprs(ref refcounter.Ref[*nftables.Set], isSource bool) ([]expr.Any, error) {
+
+	// dst offset
+	offset := uint32(16)
 	if isSource {
 		// src offset
-		offset = r.af.srcAddrOffset
+		offset = 12
 	}
 
 	return []expr.Any{
@@ -2233,7 +2146,7 @@ func (r *router) getIpSetExprs(ref refcounter.Ref[*nftables.Set], isSource bool)
 			DestRegister: 1,
 			Base:         expr.PayloadBaseNetworkHeader,
 			Offset:       offset,
-			Len:          r.af.addrLen,
+			Len:          4,
 		},
 		&expr.Lookup{
 			SourceRegister: 1,

client/firewall/nftables/router_linux_test.go

@@ -90,9 +90,8 @@ func TestNftablesManager_AddNatRule(t *testing.T) {
 				}
 
 				// Build CIDR matching expressions
-				testRouter := &router{af: afIPv4}
-				sourceExp := testRouter.applyPrefix(testCase.InputPair.Source.Prefix, true)
-				destExp := testRouter.applyPrefix(testCase.InputPair.Destination.Prefix, false)
+				sourceExp := applyPrefix(testCase.InputPair.Source.Prefix, true)
+				destExp := applyPrefix(testCase.InputPair.Destination.Prefix, false)
 
 				// Combine all expressions in the correct order
 				// nolint:gocritic
@@ -509,136 +508,6 @@ func TestNftablesCreateIpSet(t *testing.T) {
 	}
 }
 
-func TestNftablesCreateIpSet_IPv6(t *testing.T) {
-	if check() != NFTABLES {
-		t.Skip("nftables not supported on this system")
-	}
-
-	workTable, err := createWorkTableIPv6()
-	require.NoError(t, err, "Failed to create v6 work table")
-	defer deleteWorkTableIPv6()
-
-	r, err := newRouter(workTable, ifaceMock, iface.DefaultMTU)
-	require.NoError(t, err, "Failed to create router")
-	require.NoError(t, r.init(workTable))
-	defer func() {
-		require.NoError(t, r.Reset(), "Failed to reset router")
-	}()
-
-	tests := []struct {
-		name     string
-		sources  []netip.Prefix
-		expected []netip.Prefix
-	}{
-		{
-			name:    "Single IPv6",
-			sources: []netip.Prefix{netip.MustParsePrefix("2001:db8::1/128")},
-		},
-		{
-			name: "Multiple IPv6 Subnets",
-			sources: []netip.Prefix{
-				netip.MustParsePrefix("fd00::/64"),
-				netip.MustParsePrefix("2001:db8::/48"),
-				netip.MustParsePrefix("fe80::/10"),
-			},
-		},
-		{
-			name: "Overlapping IPv6",
-			sources: []netip.Prefix{
-				netip.MustParsePrefix("fd00::/48"),
-				netip.MustParsePrefix("fd00::/64"),
-				netip.MustParsePrefix("fd00::1/128"),
-			},
-			expected: []netip.Prefix{
-				netip.MustParsePrefix("fd00::/48"),
-			},
-		},
-		{
-			name: "Mixed prefix lengths",
-			sources: []netip.Prefix{
-				netip.MustParsePrefix("2001:db8:1::/48"),
-				netip.MustParsePrefix("2001:db8:2::1/128"),
-				netip.MustParsePrefix("fd00:abcd::/32"),
-			},
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			setName := firewall.NewPrefixSet(tt.sources).HashedName()
-			set, err := r.createIpSet(setName, setInput{prefixes: tt.sources})
-			require.NoError(t, err, "Failed to create IPv6 set")
-			require.NotNil(t, set)
-
-			assert.Equal(t, setName, set.Name)
-			assert.True(t, set.Interval)
-			assert.Equal(t, nftables.TypeIP6Addr, set.KeyType)
-
-			fetchedSet, err := r.conn.GetSetByName(r.workTable, setName)
-			require.NoError(t, err, "Failed to fetch created set")
-
-			elements, err := r.conn.GetSetElements(fetchedSet)
-			require.NoError(t, err, "Failed to get set elements")
-
-			uniquePrefixes := make(map[string]bool)
-			for _, elem := range elements {
-				if !elem.IntervalEnd && len(elem.Key) == 16 {
-					ip := netip.AddrFrom16([16]byte(elem.Key))
-					uniquePrefixes[ip.String()] = true
-				}
-			}
-
-			expectedCount := len(tt.expected)
-			if expectedCount == 0 {
-				expectedCount = len(tt.sources)
-			}
-			assert.Equal(t, expectedCount, len(uniquePrefixes), "unique prefix count mismatch")
-
-			r.conn.DelSet(set)
-			require.NoError(t, r.conn.Flush())
-		})
-	}
-}
-
-func createWorkTableIPv6() (*nftables.Table, error) {
-	sConn, err := nftables.New(nftables.AsLasting())
-	if err != nil {
-		return nil, err
-	}
-
-	tables, err := sConn.ListTablesOfFamily(nftables.TableFamilyIPv6)
-	if err != nil {
-		return nil, err
-	}
-	for _, t := range tables {
-		if t.Name == tableNameNetbird {
-			sConn.DelTable(t)
-		}
-	}
-
-	table := sConn.AddTable(&nftables.Table{Name: tableNameNetbird, Family: nftables.TableFamilyIPv6})
-	err = sConn.Flush()
-	return table, err
-}
-
-func deleteWorkTableIPv6() {
-	sConn, err := nftables.New(nftables.AsLasting())
-	if err != nil {
-		return
-	}
-
-	tables, err := sConn.ListTablesOfFamily(nftables.TableFamilyIPv6)
-	if err != nil {
-		return
-	}
-	for _, t := range tables {
-		if t.Name == tableNameNetbird {
-			sConn.DelTable(t)
-			_ = sConn.Flush()
-		}
-	}
-}
-
 func verifyRule(t *testing.T, rule *nftables.Rule, sources []netip.Prefix, destination netip.Prefix, proto firewall.Protocol, sPort, dPort *firewall.Port, direction firewall.RuleDirection, action firewall.Action, expectSet bool) {
 	t.Helper()
 
@@ -758,7 +627,7 @@ func containsPort(exprs []expr.Any, port *firewall.Port, isSource bool) bool {
 
 func containsProtocol(exprs []expr.Any, proto firewall.Protocol) bool {
 	var metaFound, cmpFound bool
-	expectedProto, _ := afIPv4.protoNum(proto)
+	expectedProto, _ := protoToInt(proto)
 	for _, e := range exprs {
 		switch ex := e.(type) {
 		case *expr.Meta:
@@ -985,55 +854,3 @@ func TestRouter_AddNatRule_WithStaleEntry(t *testing.T) {
 	}
 	assert.Equal(t, 1, found, "NAT rule should exist in kernel")
 }
-
-func TestCalculateLastIP(t *testing.T) {
-	tests := []struct {
-		prefix string
-		want   string
-	}{
-		{"10.0.0.0/24", "10.0.0.255"},
-		{"10.0.0.0/32", "10.0.0.0"},
-		{"0.0.0.0/0", "255.255.255.255"},
-		{"192.168.1.0/28", "192.168.1.15"},
-		{"fd00::/64", "fd00::ffff:ffff:ffff:ffff"},
-		{"fd00::/128", "fd00::"},
-		{"2001:db8::/48", "2001:db8:0:ffff:ffff:ffff:ffff:ffff"},
-		{"::/0", "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff"},
-	}
-	for _, tt := range tests {
-		t.Run(tt.prefix, func(t *testing.T) {
-			prefix := netip.MustParsePrefix(tt.prefix)
-			got := calculateLastIP(prefix)
-			assert.Equal(t, tt.want, got.String())
-		})
-	}
-}
-
-func TestConvertPrefixesToSet_IPv6(t *testing.T) {
-	r := &router{af: afIPv6}
-	prefixes := []netip.Prefix{
-		netip.MustParsePrefix("fd00::/64"),
-		netip.MustParsePrefix("2001:db8::1/128"),
-	}
-
-	elements := r.convertPrefixesToSet(prefixes)
-
-	// Each prefix produces 2 elements (start + end)
-	require.Len(t, elements, 4)
-
-	// fd00::/64 start
-	assert.Equal(t, netip.MustParseAddr("fd00::").As16(), [16]byte(elements[0].Key))
-	assert.False(t, elements[0].IntervalEnd)
-
-	// fd00::/64 end (fd00:0:0:1::, one past the last)
-	assert.Equal(t, netip.MustParseAddr("fd00:0:0:1::").As16(), [16]byte(elements[1].Key))
-	assert.True(t, elements[1].IntervalEnd)
-
-	// 2001:db8::1/128 start
-	assert.Equal(t, netip.MustParseAddr("2001:db8::1").As16(), [16]byte(elements[2].Key))
-	assert.False(t, elements[2].IntervalEnd)
-
-	// 2001:db8::1/128 end (2001:db8::2)
-	assert.Equal(t, netip.MustParseAddr("2001:db8::2").As16(), [16]byte(elements[3].Key))
-	assert.True(t, elements[3].IntervalEnd)
-}

client/firewall/uspfilter/allow_netbird_windows.go

@@ -5,10 +5,8 @@ import (
 	"os/exec"
 	"syscall"
 
-	"github.com/hashicorp/go-multierror"
 	log "github.com/sirupsen/logrus"
 
-	nberrors "github.com/netbirdio/netbird/client/errors"
 	"github.com/netbirdio/netbird/client/internal/statemanager"
 )
 
@@ -31,20 +29,15 @@ func (m *Manager) Close(*statemanager.Manager) error {
 		return nil
 	}
 
-	var merr *multierror.Error
-	if isFirewallRuleActive(firewallRuleName) {
-		if err := manageFirewallRule(firewallRuleName, deleteRule); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("remove windows firewall rule: %w", err))
-		}
+	if !isFirewallRuleActive(firewallRuleName) {
+		return nil
 	}
 
-	if isFirewallRuleActive(firewallRuleName + "-v6") {
-		if err := manageFirewallRule(firewallRuleName+"-v6", deleteRule); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("remove windows v6 firewall rule: %w", err))
-		}
+	if err := manageFirewallRule(firewallRuleName, deleteRule); err != nil {
+		return fmt.Errorf("couldn't remove windows firewall: %w", err)
 	}
 
-	return nberrors.FormatErrorOrNil(merr)
+	return nil
 }
 
 // AllowNetbird allows netbird interface traffic
@@ -53,33 +46,17 @@ func (m *Manager) AllowNetbird() error {
 		return nil
 	}
 
-	if !isFirewallRuleActive(firewallRuleName) {
-		if err := manageFirewallRule(firewallRuleName,
-			addRule,
-			"dir=in",
-			"enable=yes",
-			"action=allow",
-			"profile=any",
-			"localip="+m.wgIface.Address().IP.String(),
-		); err != nil {
-			return err
-		}
+	if isFirewallRuleActive(firewallRuleName) {
+		return nil
 	}
-
-	if v6 := m.wgIface.Address().IPv6; v6.IsValid() && !isFirewallRuleActive(firewallRuleName+"-v6") {
-		if err := manageFirewallRule(firewallRuleName+"-v6",
-			addRule,
-			"dir=in",
-			"enable=yes",
-			"action=allow",
-			"profile=any",
-			"localip="+v6.String(),
-		); err != nil {
-			return err
-		}
-	}
-
-	return nil
+	return manageFirewallRule(firewallRuleName,
+		addRule,
+		"dir=in",
+		"enable=yes",
+		"action=allow",
+		"profile=any",
+		"localip="+m.wgIface.Address().IP.String(),
+	)
 }
 
 func manageFirewallRule(ruleName string, action action, extraArgs ...string) error {

client/firewall/uspfilter/conntrack/common.go

@@ -1,9 +1,8 @@
 package conntrack
 
 import (
-	"net"
+	"fmt"
 	"net/netip"
-	"strconv"
 	"sync/atomic"
 	"time"
 
@@ -65,7 +64,5 @@ type ConnKey struct {
 }
 
 func (c ConnKey) String() string {
-	return net.JoinHostPort(c.SrcIP.Unmap().String(), strconv.Itoa(int(c.SrcPort))) +
-		" → " +
-		net.JoinHostPort(c.DstIP.Unmap().String(), strconv.Itoa(int(c.DstPort)))
+	return fmt.Sprintf("%s:%d → %s:%d", c.SrcIP.Unmap(), c.SrcPort, c.DstIP.Unmap(), c.DstPort)
 }

client/firewall/uspfilter/conntrack/common_test.go

@@ -13,54 +13,6 @@ import (
 var logger = log.NewFromLogrus(logrus.StandardLogger())
 var flowLogger = netflow.NewManager(nil, []byte{}, nil).GetLogger()
 
-func TestConnKey_String(t *testing.T) {
-	tests := []struct {
-		name   string
-		key    ConnKey
-		expect string
-	}{
-		{
-			name: "IPv4",
-			key: ConnKey{
-				SrcIP:   netip.MustParseAddr("192.168.1.1"),
-				DstIP:   netip.MustParseAddr("10.0.0.1"),
-				SrcPort: 12345,
-				DstPort: 80,
-			},
-			expect: "192.168.1.1:12345 → 10.0.0.1:80",
-		},
-		{
-			name: "IPv6",
-			key: ConnKey{
-				SrcIP:   netip.MustParseAddr("2001:db8::1"),
-				DstIP:   netip.MustParseAddr("2001:db8::2"),
-				SrcPort: 54321,
-				DstPort: 443,
-			},
-			expect: "[2001:db8::1]:54321 → [2001:db8::2]:443",
-		},
-		{
-			name: "IPv4-mapped IPv6 unmaps",
-			key: ConnKey{
-				SrcIP:   netip.MustParseAddr("::ffff:10.0.0.1"),
-				DstIP:   netip.MustParseAddr("::ffff:10.0.0.2"),
-				SrcPort: 1000,
-				DstPort: 2000,
-			},
-			expect: "10.0.0.1:1000 → 10.0.0.2:2000",
-		},
-	}
-
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			got := tc.key.String()
-			if got != tc.expect {
-				t.Errorf("got %q, want %q", got, tc.expect)
-			}
-		})
-	}
-}
-
 // Memory pressure tests
 func BenchmarkMemoryPressure(b *testing.B) {
 	b.Run("TCPHighLoad", func(b *testing.B) {

client/firewall/uspfilter/conntrack/icmp.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
-	"strconv"
 	"sync"
 	"time"
 
@@ -22,14 +21,9 @@ const (
 	// ICMPCleanupInterval is how often we check for stale ICMP connections
 	ICMPCleanupInterval = 15 * time.Second
 
-	// MaxICMPPayloadLength is the maximum length of ICMP payload we consider for original packet info.
-	// IPv4: 20-byte header + 8-byte transport = 28 bytes.
-	// IPv6: 40-byte header + 8-byte transport = 48 bytes.
-	MaxICMPPayloadLength = 48
-	// minICMPPayloadIPv4 is the minimum embedded packet length for IPv4 ICMP errors.
-	minICMPPayloadIPv4 = 28
-	// minICMPPayloadIPv6 is the minimum embedded packet length for IPv6 ICMP errors.
-	minICMPPayloadIPv6 = 48
+	// MaxICMPPayloadLength is the maximum length of ICMP payload we consider for original packet info,
+	// which includes the IP header (20 bytes) and transport header (8 bytes)
+	MaxICMPPayloadLength = 28
 )
 
 // ICMPConnKey uniquely identifies an ICMP connection
@@ -71,7 +65,7 @@ type ICMPInfo struct {
 
 // String implements fmt.Stringer for lazy evaluation in log messages
 func (info ICMPInfo) String() string {
-	if info.isErrorMessage() && info.PayloadLen >= minICMPPayloadIPv4 {
+	if info.isErrorMessage() && info.PayloadLen >= MaxICMPPayloadLength {
 		if origInfo := info.parseOriginalPacket(); origInfo != "" {
 			return fmt.Sprintf("%s (original: %s)", info.TypeCode, origInfo)
 		}
@@ -80,72 +74,42 @@ func (info ICMPInfo) String() string {
 	return info.TypeCode.String()
 }
 
-// isErrorMessage returns true if this ICMP type carries original packet info.
-// Covers both ICMPv4 and ICMPv6 error types. Without a family field we match
-// both sets; type 3 overlaps (v4 DestUnreachable / v6 TimeExceeded) so it's
-// kept as a literal.
+// isErrorMessage returns true if this ICMP type carries original packet info
 func (info ICMPInfo) isErrorMessage() bool {
 	typ := info.TypeCode.Type()
-	// ICMPv4 error types
-	if typ == layers.ICMPv4TypeDestinationUnreachable ||
-		typ == layers.ICMPv4TypeRedirect ||
-		typ == layers.ICMPv4TypeTimeExceeded ||
-		typ == layers.ICMPv4TypeParameterProblem {
-		return true
-	}
-	// ICMPv6 error types (type 3 already matched above as v4 DestUnreachable)
-	if typ == layers.ICMPv6TypeDestinationUnreachable ||
-		typ == layers.ICMPv6TypePacketTooBig ||
-		typ == layers.ICMPv6TypeParameterProblem {
-		return true
-	}
-	return false
+	return typ == 3 || // Destination Unreachable
+		typ == 5 || // Redirect
+		typ == 11 || // Time Exceeded
+		typ == 12 // Parameter Problem
 }
 
 // parseOriginalPacket extracts info about the original packet from ICMP payload
 func (info ICMPInfo) parseOriginalPacket() string {
-	if info.PayloadLen == 0 {
+	if info.PayloadLen < MaxICMPPayloadLength {
 		return ""
 	}
 
-	version := (info.PayloadData[0] >> 4) & 0xF
-
-	var protocol uint8
-	var srcIP, dstIP net.IP
-	var transportData []byte
-
-	switch version {
-	case 4:
-		if info.PayloadLen < minICMPPayloadIPv4 {
-			return ""
-		}
-		protocol = info.PayloadData[9]
-		srcIP = net.IP(info.PayloadData[12:16])
-		dstIP = net.IP(info.PayloadData[16:20])
-		transportData = info.PayloadData[20:]
-	case 6:
-		if info.PayloadLen < minICMPPayloadIPv6 {
-			return ""
-		}
-		// Next Header field in IPv6 header
-		protocol = info.PayloadData[6]
-		srcIP = net.IP(info.PayloadData[8:24])
-		dstIP = net.IP(info.PayloadData[24:40])
-		transportData = info.PayloadData[40:]
-	default:
+	// TODO: handle IPv6
+	if version := (info.PayloadData[0] >> 4) & 0xF; version != 4 {
 		return ""
 	}
 
+	protocol := info.PayloadData[9]
+	srcIP := net.IP(info.PayloadData[12:16])
+	dstIP := net.IP(info.PayloadData[16:20])
+
+	transportData := info.PayloadData[20:]
+
 	switch nftypes.Protocol(protocol) {
 	case nftypes.TCP:
 		srcPort := uint16(transportData[0])<<8 | uint16(transportData[1])
 		dstPort := uint16(transportData[2])<<8 | uint16(transportData[3])
-		return "TCP " + net.JoinHostPort(srcIP.String(), strconv.Itoa(int(srcPort))) + " → " + net.JoinHostPort(dstIP.String(), strconv.Itoa(int(dstPort)))
+		return fmt.Sprintf("TCP %s:%d → %s:%d", srcIP, srcPort, dstIP, dstPort)
 
 	case nftypes.UDP:
 		srcPort := uint16(transportData[0])<<8 | uint16(transportData[1])
 		dstPort := uint16(transportData[2])<<8 | uint16(transportData[3])
-		return "UDP " + net.JoinHostPort(srcIP.String(), strconv.Itoa(int(srcPort))) + " → " + net.JoinHostPort(dstIP.String(), strconv.Itoa(int(dstPort)))
+		return fmt.Sprintf("UDP %s:%d → %s:%d", srcIP, srcPort, dstIP, dstPort)
 
 	case nftypes.ICMP:
 		icmpType := transportData[0]
@@ -283,10 +247,9 @@ func (t *ICMPTracker) track(
 	t.sendEvent(nftypes.TypeStart, conn, ruleId)
 }
 
-// IsValidInbound checks if an inbound ICMP Echo Reply matches a tracked request.
-// Accepts both ICMPv4 (type 0) and ICMPv6 (type 129) echo replies.
+// IsValidInbound checks if an inbound ICMP Echo Reply matches a tracked request
 func (t *ICMPTracker) IsValidInbound(srcIP netip.Addr, dstIP netip.Addr, id uint16, icmpType uint8, size int) bool {
-	if icmpType != uint8(layers.ICMPv4TypeEchoReply) && icmpType != uint8(layers.ICMPv6TypeEchoReply) {
+	if icmpType != uint8(layers.ICMPv4TypeEchoReply) {
 		return false
 	}
 
@@ -338,13 +301,6 @@ func (t *ICMPTracker) cleanup() {
 	}
 }
 
-func icmpProtocolForAddr(ip netip.Addr) nftypes.Protocol {
-	if ip.Is6() {
-		return nftypes.ICMPv6
-	}
-	return nftypes.ICMP
-}
-
 // Close stops the cleanup routine and releases resources
 func (t *ICMPTracker) Close() {
 	t.tickerCancel()
@@ -360,7 +316,7 @@ func (t *ICMPTracker) sendEvent(typ nftypes.Type, conn *ICMPConnTrack, ruleID []
 		Type:      typ,
 		RuleID:    ruleID,
 		Direction: conn.Direction,
-		Protocol:  icmpProtocolForAddr(conn.SourceIP),
+		Protocol:  nftypes.ICMP, // TODO: adjust for IPv6/icmpv6
 		SourceIP:  conn.SourceIP,
 		DestIP:    conn.DestIP,
 		ICMPType:  conn.ICMPType,
@@ -378,7 +334,7 @@ func (t *ICMPTracker) sendStartEvent(direction nftypes.Direction, srcIP netip.Ad
 		Type:      nftypes.TypeStart,
 		RuleID:    ruleID,
 		Direction: direction,
-		Protocol:  icmpProtocolForAddr(srcIP),
+		Protocol:  nftypes.ICMP,
 		SourceIP:  srcIP,
 		DestIP:    dstIP,
 		ICMPType:  typ,

client/firewall/uspfilter/conntrack/icmp_test.go

@@ -5,42 +5,6 @@ import (
 	"testing"
 )
 
-func TestICMPConnKey_String(t *testing.T) {
-	tests := []struct {
-		name   string
-		key    ICMPConnKey
-		expect string
-	}{
-		{
-			name: "IPv4",
-			key: ICMPConnKey{
-				SrcIP: netip.MustParseAddr("192.168.1.1"),
-				DstIP: netip.MustParseAddr("10.0.0.1"),
-				ID:    1234,
-			},
-			expect: "192.168.1.1 → 10.0.0.1 (id 1234)",
-		},
-		{
-			name: "IPv6",
-			key: ICMPConnKey{
-				SrcIP: netip.MustParseAddr("2001:db8::1"),
-				DstIP: netip.MustParseAddr("2001:db8::2"),
-				ID:    5678,
-			},
-			expect: "2001:db8::1 → 2001:db8::2 (id 5678)",
-		},
-	}
-
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			got := tc.key.String()
-			if got != tc.expect {
-				t.Errorf("got %q, want %q", got, tc.expect)
-			}
-		})
-	}
-}
-
 func BenchmarkICMPTracker(b *testing.B) {
 	b.Run("TrackOutbound", func(b *testing.B) {
 		tracker := NewICMPTracker(DefaultICMPTimeout, logger, flowLogger)

client/firewall/uspfilter/filter.go

@@ -18,10 +18,9 @@ import (
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 	"github.com/google/uuid"
-	"github.com/hashicorp/go-multierror"
 	log "github.com/sirupsen/logrus"
+	"golang.org/x/exp/maps"
 
-	nberrors "github.com/netbirdio/netbird/client/errors"
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/firewall/uspfilter/common"
 	"github.com/netbirdio/netbird/client/firewall/uspfilter/conntrack"
@@ -36,10 +35,8 @@ import (
 const (
 	layerTypeAll = 255
 
-	// ipv4TCPHeaderMinSize represents minimum IPv4 (20) + TCP (20) header size for MSS calculation
-	ipv4TCPHeaderMinSize = 40
-	// ipv6TCPHeaderMinSize represents minimum IPv6 (40) + TCP (20) header size for MSS calculation
-	ipv6TCPHeaderMinSize = 60
+	// ipTCPHeaderMinSize represents minimum IP (20) + TCP (20) header size for MSS calculation
+	ipTCPHeaderMinSize = 40
 )
 
 // serviceKey represents a protocol/port combination for netstack service registry
@@ -126,7 +123,7 @@ type Manager struct {
 	logger         *nblog.Logger
 	flowLogger     nftypes.FlowLogger
 
-	blockRules []firewall.Rule
+	blockRule firewall.Rule
 
 	// Internal 1:1 DNAT
 	dnatEnabled  atomic.Bool
@@ -141,10 +138,9 @@ type Manager struct {
 	netstackServices     map[serviceKey]struct{}
 	netstackServiceMutex sync.RWMutex
 
-	mtu               uint16
-	mssClampValueIPv4 uint16
-	mssClampValueIPv6 uint16
-	mssClampEnabled   bool
+	mtu             uint16
+	mssClampValue   uint16
+	mssClampEnabled bool
 
 	// Only one hook per protocol is supported. Outbound direction only.
 	udpHookOut atomic.Pointer[common.PacketHook]
@@ -161,28 +157,11 @@ type decoder struct {
 	icmp4   layers.ICMPv4
 	icmp6   layers.ICMPv6
 	decoded []gopacket.LayerType
-	parser4 *gopacket.DecodingLayerParser
-	parser6 *gopacket.DecodingLayerParser
+	parser  *gopacket.DecodingLayerParser
 
 	dnatOrigPort uint16
 }
 
-// decodePacket decodes packet data using the appropriate parser based on IP version.
-func (d *decoder) decodePacket(data []byte) error {
-	if len(data) == 0 {
-		return errors.New("empty packet")
-	}
-	version := data[0] >> 4
-	switch version {
-	case 4:
-		return d.parser4.DecodeLayers(data, &d.decoded)
-	case 6:
-		return d.parser6.DecodeLayers(data, &d.decoded)
-	default:
-		return fmt.Errorf("unknown IP version %d", version)
-	}
-}
-
 // Create userspace firewall manager constructor
 func Create(iface common.IFaceMapper, disableServerRoutes bool, flowLogger nftypes.FlowLogger, mtu uint16) (*Manager, error) {
 	return create(iface, nil, disableServerRoutes, flowLogger, mtu)
@@ -240,17 +219,11 @@ func create(iface common.IFaceMapper, nativeFirewall firewall.Manager, disableSe
 				d := &decoder{
 					decoded: []gopacket.LayerType{},
 				}
-				d.parser4 = gopacket.NewDecodingLayerParser(
+				d.parser = gopacket.NewDecodingLayerParser(
 					layers.LayerTypeIPv4,
 					&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
 				)
-				d.parser4.IgnoreUnsupported = true
-
-				d.parser6 = gopacket.NewDecodingLayerParser(
-					layers.LayerTypeIPv6,
-					&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
-				)
-				d.parser6.IgnoreUnsupported = true
+				d.parser.IgnoreUnsupported = true
 				return d
 			},
 		},
@@ -276,12 +249,7 @@ func create(iface common.IFaceMapper, nativeFirewall firewall.Manager, disableSe
 
 	if !disableMSSClamping {
 		m.mssClampEnabled = true
-		if mtu > ipv4TCPHeaderMinSize {
-			m.mssClampValueIPv4 = mtu - ipv4TCPHeaderMinSize
-		}
-		if mtu > ipv6TCPHeaderMinSize {
-			m.mssClampValueIPv6 = mtu - ipv6TCPHeaderMinSize
-		}
+		m.mssClampValue = mtu - ipTCPHeaderMinSize
 	}
 	if err := m.localipmanager.UpdateLocalIPs(iface); err != nil {
 		return nil, fmt.Errorf("update local IPs: %w", err)
@@ -304,25 +272,13 @@ func create(iface common.IFaceMapper, nativeFirewall firewall.Manager, disableSe
 	return m, nil
 }
 
-// blockInvalidRouted installs drop rules for traffic to the wg overlay that
-// arrives via the routing path. v4 and v6 are independent: a v6 install
-// failure leaves v4 protection in place (and vice versa) so the returned
-// slice always contains whatever was successfully installed, even on error.
-// Callers must persist the slice so DisableRouting can clean partial state.
-func (m *Manager) blockInvalidRouted(iface common.IFaceMapper) ([]firewall.Rule, error) {
+func (m *Manager) blockInvalidRouted(iface common.IFaceMapper) (firewall.Rule, error) {
 	wgPrefix := iface.Address().Network
 	log.Debugf("blocking invalid routed traffic for %s", wgPrefix)
 
-	sources := []netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)}
-	v6Net := iface.Address().IPv6Net
-	if v6Net.IsValid() {
-		sources = append(sources, netip.PrefixFrom(netip.IPv6Unspecified(), 0))
-	}
-
-	var rules []firewall.Rule
-	v4Rule, err := m.addRouteFiltering(
+	rule, err := m.addRouteFiltering(
 		nil,
-		sources,
+		[]netip.Prefix{netip.PrefixFrom(netip.IPv4Unspecified(), 0)},
 		firewall.Network{Prefix: wgPrefix},
 		firewall.ProtocolALL,
 		nil,
@@ -330,30 +286,12 @@ func (m *Manager) blockInvalidRouted(iface common.IFaceMapper) ([]firewall.Rule,
 		firewall.ActionDrop,
 	)
 	if err != nil {
-		return rules, fmt.Errorf("block wg v4 net: %w", err)
-	}
-	rules = append(rules, v4Rule)
-
-	if v6Net.IsValid() {
-		log.Debugf("blocking invalid routed traffic for %s", v6Net)
-		v6Rule, err := m.addRouteFiltering(
-			nil,
-			sources,
-			firewall.Network{Prefix: v6Net},
-			firewall.ProtocolALL,
-			nil,
-			nil,
-			firewall.ActionDrop,
-		)
-		if err != nil {
-			return rules, fmt.Errorf("block wg v6 net: %w", err)
-		}
-		rules = append(rules, v6Rule)
+		return nil, fmt.Errorf("block wg nte : %w", err)
 	}
 
 	// TODO: Block networks that we're a client of
 
-	return rules, nil
+	return rule, nil
 }
 
 func (m *Manager) determineRouting() error {
@@ -583,7 +521,7 @@ func (m *Manager) addRouteFiltering(
 		mgmtId:     id,
 		sources:    sources,
 		dstSet:     destination.Set,
-		protoLayer: protoToLayer(proto, ipLayerFromPrefix(destination.Prefix)),
+		protoLayer: protoToLayer(proto, layers.LayerTypeIPv4),
 		srcPort:    sPort,
 		dstPort:    dPort,
 		action:     action,
@@ -674,10 +612,10 @@ func (m *Manager) Flush() error { return nil }
 // resetState clears all firewall rules and closes connection trackers.
 // Must be called with m.mutex held.
 func (m *Manager) resetState() {
-	clear(m.outgoingRules)
-	clear(m.incomingDenyRules)
-	clear(m.incomingRules)
-	clear(m.routeRulesMap)
+	maps.Clear(m.outgoingRules)
+	maps.Clear(m.incomingDenyRules)
+	maps.Clear(m.incomingRules)
+	maps.Clear(m.routeRulesMap)
 	m.routeRules = m.routeRules[:0]
 	m.udpHookOut.Store(nil)
 	m.tcpHookOut.Store(nil)
@@ -738,7 +676,11 @@ func (m *Manager) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
 	}
 
 	destinations := matches[0].destinations
-	destinations = append(destinations, prefixes...)
+	for _, prefix := range prefixes {
+		if prefix.Addr().Is4() {
+			destinations = append(destinations, prefix)
+		}
+	}
 
 	slices.SortFunc(destinations, func(a, b netip.Prefix) int {
 		cmp := a.Addr().Compare(b.Addr())
@@ -777,7 +719,7 @@ func (m *Manager) filterOutbound(packetData []byte, size int) bool {
 	d := m.decoders.Get().(*decoder)
 	defer m.decoders.Put(d)
 
-	if err := d.decodePacket(packetData); err != nil {
+	if err := d.parser.DecodeLayers(packetData, &d.decoded); err != nil {
 		return false
 	}
 
@@ -861,32 +803,12 @@ func (m *Manager) clampTCPMSS(packetData []byte, d *decoder) bool {
 		return false
 	}
 
-	var mssClampValue uint16
-	var ipHeaderSize int
-	switch d.decoded[0] {
-	case layers.LayerTypeIPv4:
-		mssClampValue = m.mssClampValueIPv4
-		ipHeaderSize = int(d.ip4.IHL) * 4
-		if ipHeaderSize < 20 {
-			return false
-		}
-	case layers.LayerTypeIPv6:
-		mssClampValue = m.mssClampValueIPv6
-		ipHeaderSize = 40
-	default:
-		return false
-	}
-
-	if mssClampValue == 0 {
-		return false
-	}
-
 	mssOptionIndex := -1
 	var currentMSS uint16
 	for i, opt := range d.tcp.Options {
 		if opt.OptionType == layers.TCPOptionKindMSS && len(opt.OptionData) == 2 {
 			currentMSS = binary.BigEndian.Uint16(opt.OptionData)
-			if currentMSS > mssClampValue {
+			if currentMSS > m.mssClampValue {
 				mssOptionIndex = i
 				break
 			}
@@ -897,15 +819,20 @@ func (m *Manager) clampTCPMSS(packetData []byte, d *decoder) bool {
 		return false
 	}
 
-	if !m.updateMSSOption(packetData, d, mssOptionIndex, mssClampValue, ipHeaderSize) {
+	ipHeaderSize := int(d.ip4.IHL) * 4
+	if ipHeaderSize < 20 {
 		return false
 	}
 
-	m.logger.Trace2("Clamped TCP MSS from %d to %d", currentMSS, mssClampValue)
+	if !m.updateMSSOption(packetData, d, mssOptionIndex, ipHeaderSize) {
+		return false
+	}
+
+	m.logger.Trace2("Clamped TCP MSS from %d to %d", currentMSS, m.mssClampValue)
 	return true
 }
 
-func (m *Manager) updateMSSOption(packetData []byte, d *decoder, mssOptionIndex int, mssClampValue uint16, ipHeaderSize int) bool {
+func (m *Manager) updateMSSOption(packetData []byte, d *decoder, mssOptionIndex, ipHeaderSize int) bool {
 	tcpHeaderStart := ipHeaderSize
 	tcpOptionsStart := tcpHeaderStart + 20
 
@@ -920,7 +847,7 @@ func (m *Manager) updateMSSOption(packetData []byte, d *decoder, mssOptionIndex
 	}
 
 	mssValueOffset := optOffset + 2
-	binary.BigEndian.PutUint16(packetData[mssValueOffset:mssValueOffset+2], mssClampValue)
+	binary.BigEndian.PutUint16(packetData[mssValueOffset:mssValueOffset+2], m.mssClampValue)
 
 	m.recalculateTCPChecksum(packetData, d, tcpHeaderStart)
 	return true
@@ -930,32 +857,18 @@ func (m *Manager) recalculateTCPChecksum(packetData []byte, d *decoder, tcpHeade
 	tcpLayer := packetData[tcpHeaderStart:]
 	tcpLength := len(packetData) - tcpHeaderStart
 
-	// Zero out existing checksum
 	tcpLayer[16] = 0
 	tcpLayer[17] = 0
 
-	// Build pseudo-header checksum based on IP version
 	var pseudoSum uint32
-	switch d.decoded[0] {
-	case layers.LayerTypeIPv4:
-		pseudoSum += uint32(d.ip4.SrcIP[0])<<8 | uint32(d.ip4.SrcIP[1])
-		pseudoSum += uint32(d.ip4.SrcIP[2])<<8 | uint32(d.ip4.SrcIP[3])
-		pseudoSum += uint32(d.ip4.DstIP[0])<<8 | uint32(d.ip4.DstIP[1])
-		pseudoSum += uint32(d.ip4.DstIP[2])<<8 | uint32(d.ip4.DstIP[3])
-		pseudoSum += uint32(d.ip4.Protocol)
-		pseudoSum += uint32(tcpLength)
-	case layers.LayerTypeIPv6:
-		for i := 0; i < 16; i += 2 {
-			pseudoSum += uint32(d.ip6.SrcIP[i])<<8 | uint32(d.ip6.SrcIP[i+1])
-		}
-		for i := 0; i < 16; i += 2 {
-			pseudoSum += uint32(d.ip6.DstIP[i])<<8 | uint32(d.ip6.DstIP[i+1])
-		}
-		pseudoSum += uint32(tcpLength)
-		pseudoSum += uint32(layers.IPProtocolTCP)
-	}
+	pseudoSum += uint32(d.ip4.SrcIP[0])<<8 | uint32(d.ip4.SrcIP[1])
+	pseudoSum += uint32(d.ip4.SrcIP[2])<<8 | uint32(d.ip4.SrcIP[3])
+	pseudoSum += uint32(d.ip4.DstIP[0])<<8 | uint32(d.ip4.DstIP[1])
+	pseudoSum += uint32(d.ip4.DstIP[2])<<8 | uint32(d.ip4.DstIP[3])
+	pseudoSum += uint32(d.ip4.Protocol)
+	pseudoSum += uint32(tcpLength)
 
-	sum := pseudoSum
+	var sum = pseudoSum
 	for i := 0; i < tcpLength-1; i += 2 {
 		sum += uint32(tcpLayer[i])<<8 | uint32(tcpLayer[i+1])
 	}
@@ -993,9 +906,6 @@ func (m *Manager) trackOutbound(d *decoder, srcIP, dstIP netip.Addr, packetData
 		}
 	case layers.LayerTypeICMPv4:
 		m.icmpTracker.TrackOutbound(srcIP, dstIP, d.icmp4.Id, d.icmp4.TypeCode, d.icmp4.Payload, size)
-	case layers.LayerTypeICMPv6:
-		id, tc := icmpv6EchoFields(d)
-		m.icmpTracker.TrackOutbound(srcIP, dstIP, id, tc, d.icmp6.Payload, size)
 	}
 }
 
@@ -1009,9 +919,6 @@ func (m *Manager) trackInbound(d *decoder, srcIP, dstIP netip.Addr, ruleID []byt
 		m.tcpTracker.TrackInbound(srcIP, dstIP, uint16(d.tcp.SrcPort), uint16(d.tcp.DstPort), flags, ruleID, size, d.dnatOrigPort)
 	case layers.LayerTypeICMPv4:
 		m.icmpTracker.TrackInbound(srcIP, dstIP, d.icmp4.Id, d.icmp4.TypeCode, ruleID, d.icmp4.Payload, size)
-	case layers.LayerTypeICMPv6:
-		id, tc := icmpv6EchoFields(d)
-		m.icmpTracker.TrackInbound(srcIP, dstIP, id, tc, ruleID, d.icmp6.Payload, size)
 	}
 
 	d.dnatOrigPort = 0
@@ -1044,19 +951,15 @@ func (m *Manager) filterInbound(packetData []byte, size int) bool {
 
 	// TODO: pass fragments of routed packets to forwarder
 	if fragment {
-		if d.decoded[0] == layers.LayerTypeIPv4 {
-			m.logger.Trace4("packet is a fragment: src=%v dst=%v id=%v flags=%v",
-				srcIP, dstIP, d.ip4.Id, d.ip4.Flags)
-		} else {
-			m.logger.Trace2("packet is an IPv6 fragment: src=%v dst=%v", srcIP, dstIP)
-		}
+		m.logger.Trace4("packet is a fragment: src=%v dst=%v id=%v flags=%v",
+			srcIP, dstIP, d.ip4.Id, d.ip4.Flags)
 		return false
 	}
 
 	// TODO: optimize port DNAT by caching matched rules in conntrack
 	if translated := m.translateInboundPortDNAT(packetData, d, srcIP, dstIP); translated {
 		// Re-decode after port DNAT translation to update port information
-		if err := d.decodePacket(packetData); err != nil {
+		if err := d.parser.DecodeLayers(packetData, &d.decoded); err != nil {
 			m.logger.Error1("failed to re-decode packet after port DNAT: %v", err)
 			return true
 		}
@@ -1065,7 +968,7 @@ func (m *Manager) filterInbound(packetData []byte, size int) bool {
 
 	if translated := m.translateInboundReverse(packetData, d); translated {
 		// Re-decode after translation to get original addresses
-		if err := d.decodePacket(packetData); err != nil {
+		if err := d.parser.DecodeLayers(packetData, &d.decoded); err != nil {
 			m.logger.Error1("failed to re-decode packet after reverse DNAT: %v", err)
 			return true
 		}
@@ -1197,48 +1100,6 @@ func (m *Manager) handleRoutedTraffic(d *decoder, srcIP, dstIP netip.Addr, packe
 	return true
 }
 
-// icmpv6EchoFields extracts the echo identifier from an ICMPv6 packet and maps
-// the ICMPv6 type code to an ICMPv4TypeCode so the ICMP conntrack can handle
-// both families uniformly. The echo ID is in the first two payload bytes.
-func icmpv6EchoFields(d *decoder) (id uint16, tc layers.ICMPv4TypeCode) {
-	if len(d.icmp6.Payload) >= 2 {
-		id = uint16(d.icmp6.Payload[0])<<8 | uint16(d.icmp6.Payload[1])
-	}
-	// Map ICMPv6 echo types to ICMPv4 equivalents for unified tracking.
-	switch d.icmp6.TypeCode.Type() {
-	case layers.ICMPv6TypeEchoRequest:
-		tc = layers.CreateICMPv4TypeCode(layers.ICMPv4TypeEchoRequest, 0)
-	case layers.ICMPv6TypeEchoReply:
-		tc = layers.CreateICMPv4TypeCode(layers.ICMPv4TypeEchoReply, 0)
-	default:
-		tc = layers.CreateICMPv4TypeCode(d.icmp6.TypeCode.Type(), d.icmp6.TypeCode.Code())
-	}
-	return id, tc
-}
-
-// protoLayerMatches checks if a packet's protocol layer matches a rule's expected
-// protocol layer. ICMPv4 and ICMPv6 are treated as equivalent when matching
-// ICMP rules since management sends a single ICMP rule for both families.
-func protoLayerMatches(ruleLayer, packetLayer gopacket.LayerType) bool {
-	if ruleLayer == packetLayer {
-		return true
-	}
-	if ruleLayer == layers.LayerTypeICMPv4 && packetLayer == layers.LayerTypeICMPv6 {
-		return true
-	}
-	if ruleLayer == layers.LayerTypeICMPv6 && packetLayer == layers.LayerTypeICMPv4 {
-		return true
-	}
-	return false
-}
-
-func ipLayerFromPrefix(p netip.Prefix) gopacket.LayerType {
-	if p.Addr().Is6() {
-		return layers.LayerTypeIPv6
-	}
-	return layers.LayerTypeIPv4
-}
-
 func protoToLayer(proto firewall.Protocol, ipLayer gopacket.LayerType) gopacket.LayerType {
 	switch proto {
 	case firewall.ProtocolTCP:
@@ -1262,10 +1123,8 @@ func getProtocolFromPacket(d *decoder) nftypes.Protocol {
 		return nftypes.TCP
 	case layers.LayerTypeUDP:
 		return nftypes.UDP
-	case layers.LayerTypeICMPv4:
+	case layers.LayerTypeICMPv4, layers.LayerTypeICMPv6:
 		return nftypes.ICMP
-	case layers.LayerTypeICMPv6:
-		return nftypes.ICMPv6
 	default:
 		return nftypes.ProtocolUnknown
 	}
@@ -1286,7 +1145,7 @@ func getPortsFromPacket(d *decoder) (srcPort, dstPort uint16) {
 // It returns true, false if the packet is valid and not a fragment.
 // It returns true, true if the packet is a fragment and valid.
 func (m *Manager) isValidPacket(d *decoder, packetData []byte) (bool, bool) {
-	if err := d.decodePacket(packetData); err != nil {
+	if err := d.parser.DecodeLayers(packetData, &d.decoded); err != nil {
 		m.logger.Trace1("couldn't decode packet, err: %s", err)
 		return false, false
 	}
@@ -1299,21 +1158,10 @@ func (m *Manager) isValidPacket(d *decoder, packetData []byte) (bool, bool) {
 	}
 
 	// Fragments are also valid
-	if l == 1 {
-		switch d.decoded[0] {
-		case layers.LayerTypeIPv4:
-			if d.ip4.Flags&layers.IPv4MoreFragments != 0 || d.ip4.FragOffset != 0 {
-				return true, true
-			}
-		case layers.LayerTypeIPv6:
-			// IPv6 uses Fragment extension header (NextHeader=44). If gopacket
-			// only decoded the IPv6 layer, the transport is in a fragment.
-			// TODO: handle non-Fragment extension headers (HopByHop, Routing,
-			// DestOpts) by walking the chain. gopacket's parser does not
-			// support them as DecodingLayers; today we drop such packets.
-			if d.ip6.NextHeader == layers.IPProtocolIPv6Fragment {
-				return true, true
-			}
+	if l == 1 && d.decoded[0] == layers.LayerTypeIPv4 {
+		ip4 := d.ip4
+		if ip4.Flags&layers.IPv4MoreFragments != 0 || ip4.FragOffset != 0 {
+			return true, true
 		}
 	}
 
@@ -1351,35 +1199,21 @@ func (m *Manager) isValidTrackedConnection(d *decoder, srcIP, dstIP netip.Addr,
 			size,
 		)
 
-	case layers.LayerTypeICMPv6:
-		id, _ := icmpv6EchoFields(d)
-		return m.icmpTracker.IsValidInbound(
-			srcIP,
-			dstIP,
-			id,
-			d.icmp6.TypeCode.Type(),
-			size,
-		)
+		// TODO: ICMPv6
 	}
 
 	return false
 }
 
-// isSpecialICMP returns true if the packet is a special ICMP error packet that should be allowed.
+// isSpecialICMP returns true if the packet is a special ICMP packet that should be allowed
 func (m *Manager) isSpecialICMP(d *decoder) bool {
-	switch d.decoded[1] {
-	case layers.LayerTypeICMPv4:
-		icmpType := d.icmp4.TypeCode.Type()
-		return icmpType == layers.ICMPv4TypeDestinationUnreachable ||
-			icmpType == layers.ICMPv4TypeTimeExceeded
-	case layers.LayerTypeICMPv6:
-		icmpType := d.icmp6.TypeCode.Type()
-		return icmpType == layers.ICMPv6TypeDestinationUnreachable ||
-			icmpType == layers.ICMPv6TypePacketTooBig ||
-			icmpType == layers.ICMPv6TypeTimeExceeded ||
-			icmpType == layers.ICMPv6TypeParameterProblem
+	if d.decoded[1] != layers.LayerTypeICMPv4 {
+		return false
 	}
-	return false
+
+	icmpType := d.icmp4.TypeCode.Type()
+	return icmpType == layers.ICMPv4TypeDestinationUnreachable ||
+		icmpType == layers.ICMPv4TypeTimeExceeded
 }
 
 func (m *Manager) peerACLsBlock(srcIP netip.Addr, d *decoder, packetData []byte) ([]byte, bool) {
@@ -1436,7 +1270,7 @@ func validateRule(ip netip.Addr, packetData []byte, rules map[string]PeerRule, d
 			return rule.mgmtId, rule.drop, true
 		}
 
-		if !protoLayerMatches(rule.protoLayer, payloadLayer) {
+		if payloadLayer != rule.protoLayer {
 			continue
 		}
 
@@ -1471,7 +1305,8 @@ func (m *Manager) routeACLsPass(srcIP, dstIP netip.Addr, protoLayer gopacket.Lay
 }
 
 func (m *Manager) ruleMatches(rule *RouteRule, srcAddr, dstAddr netip.Addr, protoLayer gopacket.LayerType, srcPort, dstPort uint16) bool {
-	if rule.protoLayer != layerTypeAll && !protoLayerMatches(rule.protoLayer, protoLayer) {
+	// TODO: handle ipv6 vs ipv4 icmp rules
+	if rule.protoLayer != layerTypeAll && rule.protoLayer != protoLayer {
 		return false
 	}
 
@@ -1532,14 +1367,13 @@ func (m *Manager) EnableRouting() error {
 		return nil
 	}
 
-	rules, err := m.blockInvalidRouted(m.wgIface)
-	// Persist whatever was installed even on partial failure, so DisableRouting
-	// can clean it up later.
-	m.blockRules = rules
+	rule, err := m.blockInvalidRouted(m.wgIface)
 	if err != nil {
 		return fmt.Errorf("block invalid routed: %w", err)
 	}
 
+	m.blockRule = rule
+
 	return nil
 }
 
@@ -1555,16 +1389,9 @@ func (m *Manager) DisableRouting() error {
 	m.routingEnabled.Store(false)
 	m.nativeRouter.Store(false)
 
-	var merr *multierror.Error
-	for _, rule := range m.blockRules {
-		if err := m.deleteRouteRule(rule); err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("delete block rule: %w", err))
-		}
-	}
-	m.blockRules = nil
-
+	// don't stop forwarder if in use by netstack
 	if m.netstack && m.localForwarding {
-		return nberrors.FormatErrorOrNil(merr)
+		return nil
 	}
 
 	fwder.Stop()
@@ -1572,7 +1399,14 @@ func (m *Manager) DisableRouting() error {
 
 	log.Debug("forwarder stopped")
 
-	return nberrors.FormatErrorOrNil(merr)
+	if m.blockRule != nil {
+		if err := m.deleteRouteRule(m.blockRule); err != nil {
+			return fmt.Errorf("delete block rule: %w", err)
+		}
+		m.blockRule = nil
+	}
+
+	return nil
 }
 
 // RegisterNetstackService registers a service as listening on the netstack for the given protocol and port
@@ -1626,8 +1460,7 @@ func (m *Manager) shouldForward(d *decoder, dstIP netip.Addr) bool {
 	}
 
 	// traffic to our other local interfaces (not NetBird IP) - always forward
-	addr := m.wgIface.Address()
-	if dstIP != addr.IP && (!addr.IPv6.IsValid() || dstIP != addr.IPv6) {
+	if dstIP != m.wgIface.Address().IP {
 		return true
 	}
 

client/firewall/uspfilter/filter_bench_test.go

@@ -1023,8 +1023,7 @@ func BenchmarkMSSClamping(b *testing.B) {
 			}()
 
 			manager.mssClampEnabled = true
-			manager.mssClampValueIPv4 = 1240
-			manager.mssClampValueIPv6 = 1220
+			manager.mssClampValue = 1240
 
 			srcIP := net.ParseIP("100.64.0.2")
 			dstIP := net.ParseIP("8.8.8.8")
@@ -1089,8 +1088,7 @@ func BenchmarkMSSClampingOverhead(b *testing.B) {
 
 			manager.mssClampEnabled = sc.enabled
 			if sc.enabled {
-				manager.mssClampValueIPv4 = 1240
-				manager.mssClampValueIPv6 = 1220
+				manager.mssClampValue = 1240
 			}
 
 			srcIP := net.ParseIP("100.64.0.2")
@@ -1143,8 +1141,7 @@ func BenchmarkMSSClampingMemory(b *testing.B) {
 			}()
 
 			manager.mssClampEnabled = true
-			manager.mssClampValueIPv4 = 1240
-			manager.mssClampValueIPv6 = 1220
+			manager.mssClampValue = 1240
 
 			srcIP := net.ParseIP("100.64.0.2")
 			dstIP := net.ParseIP("8.8.8.8")

client/firewall/uspfilter/filter_filter_test.go

@@ -539,236 +539,53 @@ func TestPeerACLFiltering(t *testing.T) {
 	}
 }
 
-func TestPeerACLFilteringIPv6(t *testing.T) {
-	localIP := netip.MustParseAddr("100.10.0.100")
-	localIPv6 := netip.MustParseAddr("fd00::100")
-	wgNet := netip.MustParsePrefix("100.10.0.0/16")
-	wgNetV6 := netip.MustParsePrefix("fd00::/64")
-
-	ifaceMock := &IFaceMock{
-		SetFilterFunc: func(device.PacketFilter) error { return nil },
-		AddressFunc: func() wgaddr.Address {
-			return wgaddr.Address{
-				IP:      localIP,
-				Network: wgNet,
-				IPv6:    localIPv6,
-				IPv6Net: wgNetV6,
-			}
-		},
-	}
-
-	manager, err := Create(ifaceMock, false, flowLogger, iface.DefaultMTU)
-	require.NoError(t, err)
-	t.Cleanup(func() { require.NoError(t, manager.Close(nil)) })
-
-	err = manager.UpdateLocalIPs()
-	require.NoError(t, err)
-
-	testCases := []struct {
-		name            string
-		srcIP           string
-		dstIP           string
-		proto           fw.Protocol
-		srcPort         uint16
-		dstPort         uint16
-		ruleIP          string
-		ruleProto       fw.Protocol
-		ruleDstPort     *fw.Port
-		ruleAction      fw.Action
-		shouldBeBlocked bool
-	}{
-		{
-			name:            "IPv6: allow TCP from peer",
-			srcIP:           "fd00::1",
-			dstIP:           "fd00::100",
-			proto:           fw.ProtocolTCP,
-			srcPort:         12345,
-			dstPort:         443,
-			ruleIP:          "fd00::1",
-			ruleProto:       fw.ProtocolTCP,
-			ruleDstPort:     &fw.Port{Values: []uint16{443}},
-			ruleAction:      fw.ActionAccept,
-			shouldBeBlocked: false,
-		},
-		{
-			name:            "IPv6: allow UDP from peer",
-			srcIP:           "fd00::1",
-			dstIP:           "fd00::100",
-			proto:           fw.ProtocolUDP,
-			srcPort:         12345,
-			dstPort:         53,
-			ruleIP:          "fd00::1",
-			ruleProto:       fw.ProtocolUDP,
-			ruleDstPort:     &fw.Port{Values: []uint16{53}},
-			ruleAction:      fw.ActionAccept,
-			shouldBeBlocked: false,
-		},
-		{
-			name:            "IPv6: allow ICMPv6 from peer",
-			srcIP:           "fd00::1",
-			dstIP:           "fd00::100",
-			proto:           fw.ProtocolICMP,
-			ruleIP:          "fd00::1",
-			ruleProto:       fw.ProtocolICMP,
-			ruleAction:      fw.ActionAccept,
-			shouldBeBlocked: false,
-		},
-		{
-			name:            "IPv6: block TCP without rule",
-			srcIP:           "fd00::2",
-			dstIP:           "fd00::100",
-			proto:           fw.ProtocolTCP,
-			srcPort:         12345,
-			dstPort:         443,
-			ruleIP:          "fd00::1",
-			ruleProto:       fw.ProtocolTCP,
-			ruleDstPort:     &fw.Port{Values: []uint16{443}},
-			ruleAction:      fw.ActionAccept,
-			shouldBeBlocked: true,
-		},
-		{
-			name:            "IPv6: drop rule",
-			srcIP:           "fd00::1",
-			dstIP:           "fd00::100",
-			proto:           fw.ProtocolTCP,
-			srcPort:         12345,
-			dstPort:         22,
-			ruleIP:          "fd00::1",
-			ruleProto:       fw.ProtocolTCP,
-			ruleDstPort:     &fw.Port{Values: []uint16{22}},
-			ruleAction:      fw.ActionDrop,
-			shouldBeBlocked: true,
-		},
-		{
-			name:            "IPv6: allow all protocols",
-			srcIP:           "fd00::1",
-			dstIP:           "fd00::100",
-			proto:           fw.ProtocolUDP,
-			srcPort:         12345,
-			dstPort:         9999,
-			ruleIP:          "fd00::1",
-			ruleProto:       fw.ProtocolALL,
-			ruleAction:      fw.ActionAccept,
-			shouldBeBlocked: false,
-		},
-		{
-			name:            "IPv6: v4 wildcard ICMP rule matches ICMPv6 via protoLayerMatches",
-			srcIP:           "fd00::1",
-			dstIP:           "fd00::100",
-			proto:           fw.ProtocolICMP,
-			ruleIP:          "0.0.0.0",
-			ruleProto:       fw.ProtocolICMP,
-			ruleAction:      fw.ActionAccept,
-			shouldBeBlocked: false,
-		},
-	}
-
-	t.Run("IPv6 implicit DROP (no rules)", func(t *testing.T) {
-		packet := createTestPacket(t, "fd00::1", "fd00::100", fw.ProtocolTCP, 12345, 443)
-		isDropped := manager.FilterInbound(packet, 0)
-		require.True(t, isDropped, "IPv6 packet should be dropped when no rules exist")
-	})
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			if tc.ruleAction == fw.ActionDrop {
-				rules, err := manager.AddPeerFiltering(nil, net.ParseIP(tc.ruleIP), fw.ProtocolALL, nil, nil, fw.ActionAccept, "")
-				require.NoError(t, err)
-				t.Cleanup(func() {
-					for _, rule := range rules {
-						require.NoError(t, manager.DeletePeerRule(rule))
-					}
-				})
-			}
-
-			rules, err := manager.AddPeerFiltering(nil, net.ParseIP(tc.ruleIP), tc.ruleProto, nil, tc.ruleDstPort, tc.ruleAction, "")
-			require.NoError(t, err)
-			require.NotEmpty(t, rules)
-			t.Cleanup(func() {
-				for _, rule := range rules {
-					require.NoError(t, manager.DeletePeerRule(rule))
-				}
-			})
-
-			packet := createTestPacket(t, tc.srcIP, tc.dstIP, tc.proto, tc.srcPort, tc.dstPort)
-			isDropped := manager.FilterInbound(packet, 0)
-			require.Equal(t, tc.shouldBeBlocked, isDropped, "packet filter result mismatch")
-		})
-	}
-}
-
 func createTestPacket(t *testing.T, srcIP, dstIP string, proto fw.Protocol, srcPort, dstPort uint16) []byte {
 	t.Helper()
 
-	src := net.ParseIP(srcIP)
-	dst := net.ParseIP(dstIP)
-
 	buf := gopacket.NewSerializeBuffer()
 	opts := gopacket.SerializeOptions{
 		ComputeChecksums: true,
 		FixLengths:       true,
 	}
 
-	// Detect address family
-	isV6 := src.To4() == nil
+	ipLayer := &layers.IPv4{
+		Version: 4,
+		TTL:     64,
+		SrcIP:   net.ParseIP(srcIP),
+		DstIP:   net.ParseIP(dstIP),
+	}
 
 	var err error
+	switch proto {
+	case fw.ProtocolTCP:
+		ipLayer.Protocol = layers.IPProtocolTCP
+		tcp := &layers.TCP{
+			SrcPort: layers.TCPPort(srcPort),
+			DstPort: layers.TCPPort(dstPort),
+		}
+		err = tcp.SetNetworkLayerForChecksum(ipLayer)
+		require.NoError(t, err)
+		err = gopacket.SerializeLayers(buf, opts, ipLayer, tcp)
 
-	if isV6 {
-		ip6 := &layers.IPv6{
-			Version:  6,
-			HopLimit: 64,
-			SrcIP:    src,
-			DstIP:    dst,
+	case fw.ProtocolUDP:
+		ipLayer.Protocol = layers.IPProtocolUDP
+		udp := &layers.UDP{
+			SrcPort: layers.UDPPort(srcPort),
+			DstPort: layers.UDPPort(dstPort),
 		}
+		err = udp.SetNetworkLayerForChecksum(ipLayer)
+		require.NoError(t, err)
+		err = gopacket.SerializeLayers(buf, opts, ipLayer, udp)
 
-		switch proto {
-		case fw.ProtocolTCP:
-			ip6.NextHeader = layers.IPProtocolTCP
-			tcp := &layers.TCP{SrcPort: layers.TCPPort(srcPort), DstPort: layers.TCPPort(dstPort)}
-			_ = tcp.SetNetworkLayerForChecksum(ip6)
-			err = gopacket.SerializeLayers(buf, opts, ip6, tcp)
-		case fw.ProtocolUDP:
-			ip6.NextHeader = layers.IPProtocolUDP
-			udp := &layers.UDP{SrcPort: layers.UDPPort(srcPort), DstPort: layers.UDPPort(dstPort)}
-			_ = udp.SetNetworkLayerForChecksum(ip6)
-			err = gopacket.SerializeLayers(buf, opts, ip6, udp)
-		case fw.ProtocolICMP:
-			ip6.NextHeader = layers.IPProtocolICMPv6
-			icmp := &layers.ICMPv6{
-				TypeCode: layers.CreateICMPv6TypeCode(layers.ICMPv6TypeEchoRequest, 0),
-			}
-			_ = icmp.SetNetworkLayerForChecksum(ip6)
-			err = gopacket.SerializeLayers(buf, opts, ip6, icmp)
-		default:
-			err = gopacket.SerializeLayers(buf, opts, ip6)
-		}
-	} else {
-		ip4 := &layers.IPv4{
-			Version: 4,
-			TTL:     64,
-			SrcIP:   src,
-			DstIP:   dst,
+	case fw.ProtocolICMP:
+		ipLayer.Protocol = layers.IPProtocolICMPv4
+		icmp := &layers.ICMPv4{
+			TypeCode: layers.CreateICMPv4TypeCode(layers.ICMPv4TypeEchoRequest, 0),
 		}
+		err = gopacket.SerializeLayers(buf, opts, ipLayer, icmp)
 
-		switch proto {
-		case fw.ProtocolTCP:
-			ip4.Protocol = layers.IPProtocolTCP
-			tcp := &layers.TCP{SrcPort: layers.TCPPort(srcPort), DstPort: layers.TCPPort(dstPort)}
-			_ = tcp.SetNetworkLayerForChecksum(ip4)
-			err = gopacket.SerializeLayers(buf, opts, ip4, tcp)
-		case fw.ProtocolUDP:
-			ip4.Protocol = layers.IPProtocolUDP
-			udp := &layers.UDP{SrcPort: layers.UDPPort(srcPort), DstPort: layers.UDPPort(dstPort)}
-			_ = udp.SetNetworkLayerForChecksum(ip4)
-			err = gopacket.SerializeLayers(buf, opts, ip4, udp)
-		case fw.ProtocolICMP:
-			ip4.Protocol = layers.IPProtocolICMPv4
-			icmp := &layers.ICMPv4{TypeCode: layers.CreateICMPv4TypeCode(layers.ICMPv4TypeEchoRequest, 0)}
-			err = gopacket.SerializeLayers(buf, opts, ip4, icmp)
-		default:
-			err = gopacket.SerializeLayers(buf, opts, ip4)
-		}
+	default:
+		err = gopacket.SerializeLayers(buf, opts, ipLayer)
 	}
 
 	require.NoError(t, err)
@@ -1681,103 +1498,3 @@ func TestRouteACLSet(t *testing.T) {
 	_, isAllowed = manager.routeACLsPass(srcIP, dstIP, protoToLayer(fw.ProtocolTCP, layers.LayerTypeIPv4), 12345, 80)
 	require.True(t, isAllowed, "After set update, traffic to the added network should be allowed")
 }
-
-// TestRouteACLFilteringIPv6 tests IPv6 route ACL matching directly via routeACLsPass.
-// Note: full FilterInbound for routed IPv6 traffic drops at the forwarder stage (IPv4-only)
-// but the ACL decision itself is correct.
-func TestRouteACLFilteringIPv6(t *testing.T) {
-	manager := setupRoutedManager(t, "10.10.0.100/16")
-
-	v6Dst := netip.MustParsePrefix("fd00:dead:beef::/48")
-	_, err := manager.AddRouteFiltering(
-		nil,
-		[]netip.Prefix{netip.MustParsePrefix("fd00::/16")},
-		fw.Network{Prefix: v6Dst},
-		fw.ProtocolTCP,
-		nil,
-		&fw.Port{Values: []uint16{80}},
-		fw.ActionAccept,
-	)
-	require.NoError(t, err)
-
-	_, err = manager.AddRouteFiltering(
-		nil,
-		[]netip.Prefix{netip.MustParsePrefix("fd00::/16")},
-		fw.Network{Prefix: netip.MustParsePrefix("fd00:dead:beef:1::/64")},
-		fw.ProtocolALL,
-		nil,
-		nil,
-		fw.ActionDrop,
-	)
-	require.NoError(t, err)
-
-	tests := []struct {
-		name    string
-		srcIP   netip.Addr
-		dstIP   netip.Addr
-		proto   gopacket.LayerType
-		srcPort uint16
-		dstPort uint16
-		allowed bool
-	}{
-		{
-			name:    "IPv6 TCP to allowed dest",
-			srcIP:   netip.MustParseAddr("fd00::1"),
-			dstIP:   netip.MustParseAddr("fd00:dead:beef::80"),
-			proto:   layers.LayerTypeTCP,
-			srcPort: 12345,
-			dstPort: 80,
-			allowed: true,
-		},
-		{
-			name:    "IPv6 TCP wrong port",
-			srcIP:   netip.MustParseAddr("fd00::1"),
-			dstIP:   netip.MustParseAddr("fd00:dead:beef::80"),
-			proto:   layers.LayerTypeTCP,
-			srcPort: 12345,
-			dstPort: 443,
-			allowed: false,
-		},
-		{
-			name:    "IPv6 UDP not matched by TCP rule",
-			srcIP:   netip.MustParseAddr("fd00::1"),
-			dstIP:   netip.MustParseAddr("fd00:dead:beef::80"),
-			proto:   layers.LayerTypeUDP,
-			srcPort: 12345,
-			dstPort: 80,
-			allowed: false,
-		},
-		{
-			name:    "IPv6 ICMPv6 matches ICMP rule via protoLayerMatches",
-			srcIP:   netip.MustParseAddr("fd00::1"),
-			dstIP:   netip.MustParseAddr("fd00:dead:beef::80"),
-			proto:   layers.LayerTypeICMPv6,
-			allowed: false,
-		},
-		{
-			name:    "IPv6 to denied subnet",
-			srcIP:   netip.MustParseAddr("fd00::1"),
-			dstIP:   netip.MustParseAddr("fd00:dead:beef:1::1"),
-			proto:   layers.LayerTypeTCP,
-			srcPort: 12345,
-			dstPort: 80,
-			allowed: false,
-		},
-		{
-			name:    "IPv6 source outside allowed range",
-			srcIP:   netip.MustParseAddr("fe80::1"),
-			dstIP:   netip.MustParseAddr("fd00:dead:beef::80"),
-			proto:   layers.LayerTypeTCP,
-			srcPort: 12345,
-			dstPort: 80,
-			allowed: false,
-		},
-	}
-
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			_, pass := manager.routeACLsPass(tc.srcIP, tc.dstIP, tc.proto, tc.srcPort, tc.dstPort)
-			require.Equal(t, tc.allowed, pass, "route ACL result mismatch")
-		})
-	}
-}

client/firewall/uspfilter/filter_routeacl_test.go

@@ -189,21 +189,21 @@ func TestBlockInvalidRoutedIdempotent(t *testing.T) {
 	})
 
 	// Call blockInvalidRouted directly multiple times
-	rules1, err := manager.blockInvalidRouted(ifaceMock)
+	rule1, err := manager.blockInvalidRouted(ifaceMock)
 	require.NoError(t, err)
-	require.NotEmpty(t, rules1)
+	require.NotNil(t, rule1)
 
-	rules2, err := manager.blockInvalidRouted(ifaceMock)
+	rule2, err := manager.blockInvalidRouted(ifaceMock)
 	require.NoError(t, err)
-	require.NotEmpty(t, rules2)
+	require.NotNil(t, rule2)
 
-	rules3, err := manager.blockInvalidRouted(ifaceMock)
+	rule3, err := manager.blockInvalidRouted(ifaceMock)
 	require.NoError(t, err)
-	require.NotEmpty(t, rules3)
+	require.NotNil(t, rule3)
 
-	// All calls should return the same v4 block rule (idempotent install).
-	assert.Equal(t, rules1[0].ID(), rules2[0].ID(), "Second call should return same v4 rule")
-	assert.Equal(t, rules2[0].ID(), rules3[0].ID(), "Third call should return same v4 rule")
+	// All should return the same rule
+	assert.Equal(t, rule1.ID(), rule2.ID(), "Second call should return same rule")
+	assert.Equal(t, rule2.ID(), rule3.ID(), "Third call should return same rule")
 
 	// Should have exactly 1 route rule
 	manager.mutex.RLock()

client/firewall/uspfilter/filter_test.go

@@ -535,16 +535,11 @@ func TestProcessOutgoingHooks(t *testing.T) {
 			d := &decoder{
 				decoded: []gopacket.LayerType{},
 			}
-			d.parser4 = gopacket.NewDecodingLayerParser(
+			d.parser = gopacket.NewDecodingLayerParser(
 				layers.LayerTypeIPv4,
 				&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
 			)
-			d.parser4.IgnoreUnsupported = true
-			d.parser6 = gopacket.NewDecodingLayerParser(
-				layers.LayerTypeIPv6,
-				&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
-			)
-			d.parser6.IgnoreUnsupported = true
+			d.parser.IgnoreUnsupported = true
 			return d
 		},
 	}
@@ -643,16 +638,11 @@ func TestStatefulFirewall_UDPTracking(t *testing.T) {
 			d := &decoder{
 				decoded: []gopacket.LayerType{},
 			}
-			d.parser4 = gopacket.NewDecodingLayerParser(
+			d.parser = gopacket.NewDecodingLayerParser(
 				layers.LayerTypeIPv4,
 				&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
 			)
-			d.parser4.IgnoreUnsupported = true
-			d.parser6 = gopacket.NewDecodingLayerParser(
-				layers.LayerTypeIPv6,
-				&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
-			)
-			d.parser6.IgnoreUnsupported = true
+			d.parser.IgnoreUnsupported = true
 			return d
 		},
 	}
@@ -1058,8 +1048,8 @@ func TestMSSClamping(t *testing.T) {
 	}()
 
 	require.True(t, manager.mssClampEnabled, "MSS clamping should be enabled by default")
-	require.Equal(t, uint16(1280-ipv4TCPHeaderMinSize), manager.mssClampValueIPv4, "IPv4 MSS clamp value should be MTU - 40")
-	require.Equal(t, uint16(1280-ipv6TCPHeaderMinSize), manager.mssClampValueIPv6, "IPv6 MSS clamp value should be MTU - 60")
+	expectedMSSValue := uint16(1280 - ipTCPHeaderMinSize)
+	require.Equal(t, expectedMSSValue, manager.mssClampValue, "MSS clamp value should be MTU - 40")
 
 	err = manager.UpdateLocalIPs()
 	require.NoError(t, err)
@@ -1077,7 +1067,7 @@ func TestMSSClamping(t *testing.T) {
 		require.Len(t, d.tcp.Options, 1, "Should have MSS option")
 		require.Equal(t, uint8(layers.TCPOptionKindMSS), uint8(d.tcp.Options[0].OptionType))
 		actualMSS := binary.BigEndian.Uint16(d.tcp.Options[0].OptionData)
-		require.Equal(t, manager.mssClampValueIPv4, actualMSS, "MSS should be clamped to MTU - 40")
+		require.Equal(t, expectedMSSValue, actualMSS, "MSS should be clamped to MTU - 40")
 	})
 
 	t.Run("SYN packet with low MSS unchanged", func(t *testing.T) {
@@ -1101,7 +1091,7 @@ func TestMSSClamping(t *testing.T) {
 		d := parsePacket(t, packet)
 		require.Len(t, d.tcp.Options, 1, "Should have MSS option")
 		actualMSS := binary.BigEndian.Uint16(d.tcp.Options[0].OptionData)
-		require.Equal(t, manager.mssClampValueIPv4, actualMSS, "MSS in SYN-ACK should be clamped")
+		require.Equal(t, expectedMSSValue, actualMSS, "MSS in SYN-ACK should be clamped")
 	})
 
 	t.Run("Non-SYN packet unchanged", func(t *testing.T) {
@@ -1273,18 +1263,13 @@ func TestShouldForward(t *testing.T) {
 		d := &decoder{
 			decoded: []gopacket.LayerType{},
 		}
-		d.parser4 = gopacket.NewDecodingLayerParser(
+		d.parser = gopacket.NewDecodingLayerParser(
 			layers.LayerTypeIPv4,
 			&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
 		)
-		d.parser4.IgnoreUnsupported = true
-		d.parser6 = gopacket.NewDecodingLayerParser(
-			layers.LayerTypeIPv6,
-			&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
-		)
-		d.parser6.IgnoreUnsupported = true
+		d.parser.IgnoreUnsupported = true
 
-		err = d.decodePacket(buf.Bytes())
+		err = d.parser.DecodeLayers(buf.Bytes(), &d.decoded)
 		require.NoError(t, err)
 
 		return d
@@ -1344,44 +1329,6 @@ func TestShouldForward(t *testing.T) {
 		},
 	}
 
-	// Add IPv6 to the interface and test dual-stack cases
-	wgIPv6 := netip.MustParseAddr("fd00::1")
-	otherIPv6 := netip.MustParseAddr("fd00::2")
-	ifaceMock.AddressFunc = func() wgaddr.Address {
-		return wgaddr.Address{
-			IP:      wgIP,
-			Network: netip.PrefixFrom(wgIP, 24),
-			IPv6:    wgIPv6,
-			IPv6Net: netip.PrefixFrom(wgIPv6, 64),
-		}
-	}
-
-	// Re-create manager to pick up the new address with IPv6
-	require.NoError(t, manager.Close(nil))
-	manager, err = Create(ifaceMock, false, flowLogger, nbiface.DefaultMTU)
-	require.NoError(t, err)
-
-	v6Cases := []struct {
-		name        string
-		dstIP       netip.Addr
-		expected    bool
-		description string
-	}{
-		{"v6 traffic to other address", otherIPv6, true, "should forward v6 traffic not destined to our v6 address"},
-		{"v6 traffic to our v6 IP", wgIPv6, false, "should not forward traffic destined to our v6 address"},
-		{"v4 traffic to other with v6 configured", otherIP, true, "should forward v4 traffic when v6 configured"},
-		{"v4 traffic to our v4 IP with v6 configured", wgIP, false, "should not forward traffic to our v4 address"},
-	}
-	for _, tt := range v6Cases {
-		t.Run(tt.name, func(t *testing.T) {
-			manager.localForwarding = true
-			manager.netstack = false
-			decoder := createTCPDecoder(8080)
-			result := manager.shouldForward(decoder, tt.dstIP)
-			require.Equal(t, tt.expected, result, tt.description)
-		})
-	}
-
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			// Configure manager

client/firewall/uspfilter/forwarder/endpoint.go

@@ -1,8 +1,7 @@
 package forwarder
 
 import (
-	"net"
-	"strconv"
+	"fmt"
 	"sync/atomic"
 
 	wgdevice "golang.zx2c4.com/wireguard/device"
@@ -55,23 +54,16 @@ func (e *endpoint) LinkAddress() tcpip.LinkAddress {
 func (e *endpoint) WritePackets(pkts stack.PacketBufferList) (int, tcpip.Error) {
 	var written int
 	for _, pkt := range pkts.AsSlice() {
+		netHeader := header.IPv4(pkt.NetworkHeader().View().AsSlice())
+
 		data := stack.PayloadSince(pkt.NetworkHeader())
 		if data == nil {
 			continue
 		}
 
-		raw := pkt.NetworkHeader().View().AsSlice()
-		if len(raw) == 0 {
-			continue
-		}
-		var address tcpip.Address
-		if raw[0]>>4 == 6 {
-			address = header.IPv6(raw).DestinationAddress()
-		} else {
-			address = header.IPv4(raw).DestinationAddress()
-		}
-
 		pktBytes := data.AsSlice()
+
+		address := netHeader.DestinationAddress()
 		if err := e.device.CreateOutboundPacket(pktBytes, address.AsSlice()); err != nil {
 			e.logger.Error1("CreateOutboundPacket: %v", err)
 			continue
@@ -122,7 +114,5 @@ type epID stack.TransportEndpointID
 
 func (i epID) String() string {
 	// src and remote is swapped
-	return net.JoinHostPort(i.RemoteAddress.String(), strconv.Itoa(int(i.RemotePort))) +
-		" → " +
-		net.JoinHostPort(i.LocalAddress.String(), strconv.Itoa(int(i.LocalPort)))
+	return fmt.Sprintf("%s:%d → %s:%d", i.RemoteAddress, i.RemotePort, i.LocalAddress, i.LocalPort)
 }

client/firewall/uspfilter/forwarder/forwarder.go

@@ -14,7 +14,6 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
-	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/icmp"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
@@ -37,31 +36,25 @@ type Forwarder struct {
 	logger     *nblog.Logger
 	flowLogger nftypes.FlowLogger
 	// ruleIdMap is used to store the rule ID for a given connection
-	ruleIdMap          sync.Map
-	stack              *stack.Stack
-	endpoint           *endpoint
-	udpForwarder       *udpForwarder
-	ctx                context.Context
-	cancel             context.CancelFunc
-	ip                 tcpip.Address
-	ipv6               tcpip.Address
-	netstack           bool
-	hasRawICMPAccess   bool
-	hasRawICMPv6Access bool
-	pingSemaphore      chan struct{}
+	ruleIdMap        sync.Map
+	stack            *stack.Stack
+	endpoint         *endpoint
+	udpForwarder     *udpForwarder
+	ctx              context.Context
+	cancel           context.CancelFunc
+	ip               tcpip.Address
+	netstack         bool
+	hasRawICMPAccess bool
+	pingSemaphore    chan struct{}
 }
 
 func New(iface common.IFaceMapper, logger *nblog.Logger, flowLogger nftypes.FlowLogger, netstack bool, mtu uint16) (*Forwarder, error) {
 	s := stack.New(stack.Options{
-		NetworkProtocols: []stack.NetworkProtocolFactory{
-			ipv4.NewProtocol,
-			ipv6.NewProtocol,
-		},
+		NetworkProtocols: []stack.NetworkProtocolFactory{ipv4.NewProtocol},
 		TransportProtocols: []stack.TransportProtocolFactory{
 			tcp.NewProtocol,
 			udp.NewProtocol,
 			icmp.NewProtocol4,
-			icmp.NewProtocol6,
 		},
 		HandleLocal: false,
 	})
@@ -80,7 +73,7 @@ func New(iface common.IFaceMapper, logger *nblog.Logger, flowLogger nftypes.Flow
 	protoAddr := tcpip.ProtocolAddress{
 		Protocol: ipv4.ProtocolNumber,
 		AddressWithPrefix: tcpip.AddressWithPrefix{
-			Address:   tcpip.AddrFrom4(iface.Address().IP.As4()),
+			Address:   tcpip.AddrFromSlice(iface.Address().IP.AsSlice()),
 			PrefixLen: iface.Address().Network.Bits(),
 		},
 	}
@@ -89,19 +82,6 @@ func New(iface common.IFaceMapper, logger *nblog.Logger, flowLogger nftypes.Flow
 		return nil, fmt.Errorf("failed to add protocol address: %s", err)
 	}
 
-	if v6 := iface.Address().IPv6; v6.IsValid() {
-		v6Addr := tcpip.ProtocolAddress{
-			Protocol: ipv6.ProtocolNumber,
-			AddressWithPrefix: tcpip.AddressWithPrefix{
-				Address:   tcpip.AddrFrom16(v6.As16()),
-				PrefixLen: iface.Address().IPv6Net.Bits(),
-			},
-		}
-		if err := s.AddProtocolAddress(nicID, v6Addr, stack.AddressProperties{}); err != nil {
-			return nil, fmt.Errorf("add IPv6 protocol address: %s", err)
-		}
-	}
-
 	defaultSubnet, err := tcpip.NewSubnet(
 		tcpip.AddrFrom4([4]byte{0, 0, 0, 0}),
 		tcpip.MaskFromBytes([]byte{0, 0, 0, 0}),
@@ -110,14 +90,6 @@ func New(iface common.IFaceMapper, logger *nblog.Logger, flowLogger nftypes.Flow
 		return nil, fmt.Errorf("creating default subnet: %w", err)
 	}
 
-	defaultSubnetV6, err := tcpip.NewSubnet(
-		tcpip.AddrFrom16([16]byte{}),
-		tcpip.MaskFromBytes(make([]byte, 16)),
-	)
-	if err != nil {
-		return nil, fmt.Errorf("creating default v6 subnet: %w", err)
-	}
-
 	if err := s.SetPromiscuousMode(nicID, true); err != nil {
 		return nil, fmt.Errorf("set promiscuous mode: %s", err)
 	}
@@ -126,8 +98,10 @@ func New(iface common.IFaceMapper, logger *nblog.Logger, flowLogger nftypes.Flow
 	}
 
 	s.SetRouteTable([]tcpip.Route{
-		{Destination: defaultSubnet, NIC: nicID},
-		{Destination: defaultSubnetV6, NIC: nicID},
+		{
+			Destination: defaultSubnet,
+			NIC:         nicID,
+		},
 	})
 
 	ctx, cancel := context.WithCancel(context.Background())
@@ -140,8 +114,7 @@ func New(iface common.IFaceMapper, logger *nblog.Logger, flowLogger nftypes.Flow
 		ctx:           ctx,
 		cancel:        cancel,
 		netstack:      netstack,
-		ip:            tcpip.AddrFrom4(iface.Address().IP.As4()),
-		ipv6:          addrFromNetipAddr(iface.Address().IPv6),
+		ip:            tcpip.AddrFromSlice(iface.Address().IP.AsSlice()),
 		pingSemaphore: make(chan struct{}, 3),
 	}
 
@@ -158,10 +131,7 @@ func New(iface common.IFaceMapper, logger *nblog.Logger, flowLogger nftypes.Flow
 	udpForwarder := udp.NewForwarder(s, f.handleUDP)
 	s.SetTransportProtocolHandler(udp.ProtocolNumber, udpForwarder.HandlePacket)
 
-	// ICMP is handled directly in InjectIncomingPacket, bypassing gVisor's
-	// network layer. This avoids duplicate echo replies (v4) and the v6
-	// auto-reply bug where gVisor responds at the network layer before
-	// our transport handler fires.
+	s.SetTransportProtocolHandler(icmp.ProtocolNumber4, f.handleICMP)
 
 	f.checkICMPCapability()
 
@@ -180,30 +150,8 @@ func (f *Forwarder) SetCapture(pc PacketCapture) {
 }
 
 func (f *Forwarder) InjectIncomingPacket(payload []byte) error {
-	if len(payload) == 0 {
-		return fmt.Errorf("empty packet")
-	}
-
-	var protoNum tcpip.NetworkProtocolNumber
-	switch payload[0] >> 4 {
-	case 4:
-		if len(payload) < header.IPv4MinimumSize {
-			return fmt.Errorf("IPv4 packet too small: %d bytes", len(payload))
-		}
-		if f.handleICMPDirect(payload) {
-			return nil
-		}
-		protoNum = ipv4.ProtocolNumber
-	case 6:
-		if len(payload) < header.IPv6MinimumSize {
-			return fmt.Errorf("IPv6 packet too small: %d bytes", len(payload))
-		}
-		if f.handleICMPDirect(payload) {
-			return nil
-		}
-		protoNum = ipv6.ProtocolNumber
-	default:
-		return fmt.Errorf("unknown IP version: %d", payload[0]>>4)
+	if len(payload) < header.IPv4MinimumSize {
+		return fmt.Errorf("packet too small: %d bytes", len(payload))
 	}
 
 	pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
@@ -212,160 +160,11 @@ func (f *Forwarder) InjectIncomingPacket(payload []byte) error {
 	defer pkt.DecRef()
 
 	if f.endpoint.dispatcher != nil {
-		f.endpoint.dispatcher.DeliverNetworkPacket(protoNum, pkt)
+		f.endpoint.dispatcher.DeliverNetworkPacket(ipv4.ProtocolNumber, pkt)
 	}
 	return nil
 }
 
-// handleICMPDirect intercepts ICMP packets from raw IP payloads before they
-// enter gVisor. It synthesizes the TransportEndpointID and PacketBuffer that
-// the existing handlers expect, then dispatches to handleICMP/handleICMPv6.
-// This bypasses gVisor's network layer which causes duplicate v4 echo replies
-// and auto-replies to all v6 echo requests in promiscuous mode.
-//
-// Unlike gVisor's network layer, this does not validate ICMP checksums or
-// reassemble IP fragments. Fragmented ICMP packets fall through to gVisor.
-func parseICMPv4(payload []byte) (ipHdrLen, icmpLen int, src, dst tcpip.Address, ok bool) {
-	if len(payload) < header.IPv4MinimumSize {
-		return 0, 0, src, dst, false
-	}
-	ip := header.IPv4(payload)
-	if ip.Protocol() != uint8(header.ICMPv4ProtocolNumber) {
-		return 0, 0, src, dst, false
-	}
-	if ip.FragmentOffset() != 0 || ip.Flags()&header.IPv4FlagMoreFragments != 0 {
-		return 0, 0, src, dst, false
-	}
-	ipHdrLen = int(ip.HeaderLength())
-	totalLen := int(ip.TotalLength())
-	if ipHdrLen < header.IPv4MinimumSize || ipHdrLen > totalLen || totalLen > len(payload) {
-		return 0, 0, src, dst, false
-	}
-	icmpLen = totalLen - ipHdrLen
-	if icmpLen < header.ICMPv4MinimumSize {
-		return 0, 0, src, dst, false
-	}
-	return ipHdrLen, icmpLen, ip.SourceAddress(), ip.DestinationAddress(), true
-}
-
-func parseICMPv6(payload []byte) (ipHdrLen, icmpLen int, src, dst tcpip.Address, ok bool) {
-	if len(payload) < header.IPv6MinimumSize {
-		return 0, 0, src, dst, false
-	}
-	ip := header.IPv6(payload)
-	declaredLen := int(ip.PayloadLength())
-	hdrEnd := header.IPv6MinimumSize + declaredLen
-	if hdrEnd > len(payload) {
-		return 0, 0, src, dst, false
-	}
-	icmpStart, ok := skipIPv6ExtensionsToICMPv6(payload, ip.NextHeader(), hdrEnd)
-	if !ok {
-		return 0, 0, src, dst, false
-	}
-	icmpLen = hdrEnd - icmpStart
-	if icmpLen < header.ICMPv6MinimumSize {
-		return 0, 0, src, dst, false
-	}
-	return icmpStart, icmpLen, ip.SourceAddress(), ip.DestinationAddress(), true
-}
-
-// skipIPv6ExtensionsToICMPv6 walks the IPv6 extension-header chain starting
-// after the fixed header. It advances past Hop-by-Hop, Routing, and
-// Destination Options headers (which share the NextHeader+ExtLen+6+ExtLen*8
-// layout) and returns the offset of the ICMPv6 payload. Fragment, ESP, AH,
-// and unknown identifiers are reported as not handleable so the caller can
-// defer to gVisor.
-func skipIPv6ExtensionsToICMPv6(payload []byte, next uint8, hdrEnd int) (int, bool) {
-	off := header.IPv6MinimumSize
-	for {
-		if next == uint8(header.ICMPv6ProtocolNumber) {
-			return off, true
-		}
-		if !isWalkableIPv6ExtHdr(next) {
-			return 0, false
-		}
-		newOff, newNext, ok := advanceIPv6ExtHdr(payload, off, hdrEnd)
-		if !ok {
-			return 0, false
-		}
-		off = newOff
-		next = newNext
-	}
-}
-
-func isWalkableIPv6ExtHdr(id uint8) bool {
-	switch id {
-	case uint8(header.IPv6HopByHopOptionsExtHdrIdentifier),
-		uint8(header.IPv6RoutingExtHdrIdentifier),
-		uint8(header.IPv6DestinationOptionsExtHdrIdentifier):
-		return true
-	}
-	return false
-}
-
-func advanceIPv6ExtHdr(payload []byte, off, hdrEnd int) (int, uint8, bool) {
-	if off+8 > hdrEnd {
-		return 0, 0, false
-	}
-	extLen := (int(payload[off+1]) + 1) * 8
-	if off+extLen > hdrEnd {
-		return 0, 0, false
-	}
-	return off + extLen, payload[off], true
-}
-
-func (f *Forwarder) handleICMPDirect(payload []byte) bool {
-	if len(payload) == 0 {
-		return false
-	}
-	var (
-		ipHdrLen int
-		icmpLen  int
-		srcAddr  tcpip.Address
-		dstAddr  tcpip.Address
-		ok       bool
-	)
-	version := payload[0] >> 4
-	switch version {
-	case 4:
-		ipHdrLen, icmpLen, srcAddr, dstAddr, ok = parseICMPv4(payload)
-	case 6:
-		ipHdrLen, icmpLen, srcAddr, dstAddr, ok = parseICMPv6(payload)
-	}
-	if !ok {
-		return false
-	}
-
-	// Let gVisor handle ICMP destined for our own addresses natively.
-	// Its network-layer auto-reply is correct and efficient for local traffic.
-	if f.ip.Equal(dstAddr) || f.ipv6.Equal(dstAddr) {
-		return false
-	}
-
-	id := stack.TransportEndpointID{
-		LocalAddress:  dstAddr,
-		RemoteAddress: srcAddr,
-	}
-
-	// Trim the buffer to the IP-declared length so gVisor doesn't see padding.
-	pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
-		Payload: buffer.MakeWithData(payload[:ipHdrLen+icmpLen]),
-	})
-	defer pkt.DecRef()
-
-	if _, ok := pkt.NetworkHeader().Consume(ipHdrLen); !ok {
-		return false
-	}
-	if _, ok := pkt.TransportHeader().Consume(icmpLen); !ok {
-		return false
-	}
-
-	if version == 6 {
-		return f.handleICMPv6(id, pkt)
-	}
-	return f.handleICMP(id, pkt)
-}
-
 // Stop gracefully shuts down the forwarder
 func (f *Forwarder) Stop() {
 	f.cancel()
@@ -378,14 +177,11 @@ func (f *Forwarder) Stop() {
 	f.stack.Wait()
 }
 
-func (f *Forwarder) determineDialAddr(addr tcpip.Address) netip.Addr {
+func (f *Forwarder) determineDialAddr(addr tcpip.Address) net.IP {
 	if f.netstack && f.ip.Equal(addr) {
-		return netip.AddrFrom4([4]byte{127, 0, 0, 1})
+		return net.IPv4(127, 0, 0, 1)
 	}
-	if f.netstack && f.ipv6.Equal(addr) {
-		return netip.IPv6Loopback()
-	}
-	return addrToNetipAddr(addr)
+	return addr.AsSlice()
 }
 
 func (f *Forwarder) RegisterRuleID(srcIP, dstIP netip.Addr, srcPort, dstPort uint16, ruleID []byte) {
@@ -419,50 +215,23 @@ func buildKey(srcIP, dstIP netip.Addr, srcPort, dstPort uint16) conntrack.ConnKe
 	}
 }
 
-// addrFromNetipAddr converts a netip.Addr to a gvisor tcpip.Address without allocating.
-func addrFromNetipAddr(addr netip.Addr) tcpip.Address {
-	if !addr.IsValid() {
-		return tcpip.Address{}
-	}
-	if addr.Is4() {
-		return tcpip.AddrFrom4(addr.As4())
-	}
-	return tcpip.AddrFrom16(addr.As16())
-}
-
-// addrToNetipAddr converts a gvisor tcpip.Address to netip.Addr without allocating.
-func addrToNetipAddr(addr tcpip.Address) netip.Addr {
-	switch addr.Len() {
-	case 4:
-		return netip.AddrFrom4(addr.As4())
-	case 16:
-		return netip.AddrFrom16(addr.As16())
-	default:
-		return netip.Addr{}
-	}
-}
-
 // checkICMPCapability tests whether we have raw ICMP socket access at startup.
 func (f *Forwarder) checkICMPCapability() {
-	f.hasRawICMPAccess = probeRawICMP("ip4:icmp", "0.0.0.0", f.logger)
-	f.hasRawICMPv6Access = probeRawICMP("ip6:ipv6-icmp", "::", f.logger)
-}
-
-func probeRawICMP(network, addr string, logger *nblog.Logger) bool {
 	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
 	defer cancel()
 
 	lc := net.ListenConfig{}
-	conn, err := lc.ListenPacket(ctx, network, addr)
+	conn, err := lc.ListenPacket(ctx, "ip4:icmp", "0.0.0.0")
 	if err != nil {
-		logger.Debug1("forwarder: no raw %s socket access, will use ping binary fallback", network)
-		return false
+		f.hasRawICMPAccess = false
+		f.logger.Debug("forwarder: No raw ICMP socket access, will use ping binary fallback")
+		return
 	}
 
 	if err := conn.Close(); err != nil {
-		logger.Debug2("forwarder: failed to close %s capability test socket: %v", network, err)
+		f.logger.Debug1("forwarder: Failed to close ICMP capability test socket: %v", err)
 	}
 
-	logger.Debug1("forwarder: raw %s socket access available", network)
-	return true
+	f.hasRawICMPAccess = true
+	f.logger.Debug("forwarder: Raw ICMP socket access available")
 }

client/firewall/uspfilter/forwarder/forwarder_test.go

@@ -1,162 +0,0 @@
-package forwarder
-
-import (
-	"net/netip"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	"gvisor.dev/gvisor/pkg/tcpip"
-	"gvisor.dev/gvisor/pkg/tcpip/header"
-)
-
-const echoRequestSize = 8
-
-func makeIPv6(t *testing.T, src, dst netip.Addr, nextHdr uint8, payload []byte) []byte {
-	t.Helper()
-	buf := make([]byte, header.IPv6MinimumSize+len(payload))
-	ip := header.IPv6(buf)
-	ip.Encode(&header.IPv6Fields{
-		PayloadLength:     uint16(len(payload)),
-		TransportProtocol: 0, // overwritten below to allow any value
-		HopLimit:          64,
-		SrcAddr:           tcpipAddrFromNetip(src),
-		DstAddr:           tcpipAddrFromNetip(dst),
-	})
-	buf[6] = nextHdr
-	copy(buf[header.IPv6MinimumSize:], payload)
-	return buf
-}
-
-func tcpipAddrFromNetip(a netip.Addr) tcpip.Address {
-	b := a.As16()
-	return tcpip.AddrFrom16(b)
-}
-
-func echoRequest() []byte {
-	icmp := make([]byte, echoRequestSize)
-	icmp[0] = uint8(header.ICMPv6EchoRequest)
-	return icmp
-}
-
-// extHdr builds a generic IPv6 extension header (HBH/Routing/DestOpts) of the
-// given total octet length (must be multiple of 8, >= 8) with the given next
-// header.
-func extHdr(t *testing.T, next uint8, totalLen int) []byte {
-	t.Helper()
-	require.GreaterOrEqual(t, totalLen, 8)
-	require.Equal(t, 0, totalLen%8)
-	buf := make([]byte, totalLen)
-	buf[0] = next
-	buf[1] = uint8(totalLen/8 - 1)
-	return buf
-}
-
-func TestParseICMPv6_NoExtensions(t *testing.T) {
-	src := netip.MustParseAddr("fd00::1")
-	dst := netip.MustParseAddr("fd00::2")
-	pkt := makeIPv6(t, src, dst, uint8(header.ICMPv6ProtocolNumber), echoRequest())
-
-	off, icmpLen, _, _, ok := parseICMPv6(pkt)
-	require.True(t, ok)
-	assert.Equal(t, header.IPv6MinimumSize, off)
-	assert.Equal(t, echoRequestSize, icmpLen)
-}
-
-func TestParseICMPv6_SingleExtension(t *testing.T) {
-	src := netip.MustParseAddr("fd00::1")
-	dst := netip.MustParseAddr("fd00::2")
-	hbh := extHdr(t, uint8(header.ICMPv6ProtocolNumber), 8)
-	payload := append([]byte{}, hbh...)
-	payload = append(payload, echoRequest()...)
-	pkt := makeIPv6(t, src, dst, uint8(header.IPv6HopByHopOptionsExtHdrIdentifier), payload)
-
-	off, icmpLen, _, _, ok := parseICMPv6(pkt)
-	require.True(t, ok)
-	assert.Equal(t, header.IPv6MinimumSize+8, off)
-	assert.Equal(t, echoRequestSize, icmpLen)
-}
-
-func TestParseICMPv6_ChainedExtensions(t *testing.T) {
-	src := netip.MustParseAddr("fd00::1")
-	dst := netip.MustParseAddr("fd00::2")
-	dest := extHdr(t, uint8(header.ICMPv6ProtocolNumber), 16)
-	rt := extHdr(t, uint8(header.IPv6DestinationOptionsExtHdrIdentifier), 8)
-	hbh := extHdr(t, uint8(header.IPv6RoutingExtHdrIdentifier), 8)
-	payload := append(append(append([]byte{}, hbh...), rt...), dest...)
-	payload = append(payload, echoRequest()...)
-	pkt := makeIPv6(t, src, dst, uint8(header.IPv6HopByHopOptionsExtHdrIdentifier), payload)
-
-	off, icmpLen, _, _, ok := parseICMPv6(pkt)
-	require.True(t, ok)
-	assert.Equal(t, header.IPv6MinimumSize+8+8+16, off)
-	assert.Equal(t, echoRequestSize, icmpLen)
-}
-
-func TestParseICMPv6_FragmentDefersToGVisor(t *testing.T) {
-	src := netip.MustParseAddr("fd00::1")
-	dst := netip.MustParseAddr("fd00::2")
-	pkt := makeIPv6(t, src, dst, uint8(header.IPv6FragmentExtHdrIdentifier), make([]byte, 8))
-
-	_, _, _, _, ok := parseICMPv6(pkt)
-	assert.False(t, ok)
-}
-
-func TestParseICMPv6_TruncatedExtension(t *testing.T) {
-	src := netip.MustParseAddr("fd00::1")
-	dst := netip.MustParseAddr("fd00::2")
-	// Extension claims 16 bytes but only 8 remain after the IP header.
-	hbh := []byte{uint8(header.ICMPv6ProtocolNumber), 1, 0, 0, 0, 0, 0, 0}
-	pkt := makeIPv6(t, src, dst, uint8(header.IPv6HopByHopOptionsExtHdrIdentifier), hbh)
-
-	_, _, _, _, ok := parseICMPv6(pkt)
-	assert.False(t, ok)
-}
-
-func TestParseICMPv6_TruncatedICMPPayload(t *testing.T) {
-	src := netip.MustParseAddr("fd00::1")
-	dst := netip.MustParseAddr("fd00::2")
-	// PayloadLength claims 8 bytes of ICMPv6 but the buffer only holds 4.
-	pkt := makeIPv6(t, src, dst, uint8(header.ICMPv6ProtocolNumber), make([]byte, 8))
-	pkt = pkt[:header.IPv6MinimumSize+4]
-
-	_, _, _, _, ok := parseICMPv6(pkt)
-	assert.False(t, ok)
-}
-
-func TestParseICMPv4_RejectsShortIHL(t *testing.T) {
-	pkt := make([]byte, 28)
-	pkt[0] = 0x44 // version 4, IHL 4 (16 bytes - below minimum)
-	pkt[9] = uint8(header.ICMPv4ProtocolNumber)
-	header.IPv4(pkt).SetTotalLength(28)
-
-	_, _, _, _, ok := parseICMPv4(pkt)
-	assert.False(t, ok)
-}
-
-func TestParseICMPv4_RejectsTotalLenOverBuffer(t *testing.T) {
-	pkt := make([]byte, header.IPv4MinimumSize+header.ICMPv4MinimumSize)
-	ip := header.IPv4(pkt)
-	ip.Encode(&header.IPv4Fields{
-		TotalLength: uint16(len(pkt) + 16),
-		Protocol:    uint8(header.ICMPv4ProtocolNumber),
-		TTL:         64,
-	})
-
-	_, _, _, _, ok := parseICMPv4(pkt)
-	assert.False(t, ok)
-}
-
-func TestParseICMPv4_RejectsFragment(t *testing.T) {
-	pkt := make([]byte, header.IPv4MinimumSize+header.ICMPv4MinimumSize)
-	ip := header.IPv4(pkt)
-	ip.Encode(&header.IPv4Fields{
-		TotalLength: uint16(len(pkt)),
-		Protocol:    uint8(header.ICMPv4ProtocolNumber),
-		TTL:         64,
-		Flags:       header.IPv4FlagMoreFragments,
-	})
-
-	_, _, _, _, ok := parseICMPv4(pkt)
-	assert.False(t, ok)
-}

client/firewall/uspfilter/forwarder/icmp.go

@@ -35,7 +35,7 @@ func (f *Forwarder) handleICMP(id stack.TransportEndpointID, pkt *stack.PacketBu
 	}
 
 	icmpData := stack.PayloadSince(pkt.TransportHeader()).AsSlice()
-	conn, err := f.forwardICMPPacket(id, icmpData, uint8(icmpHdr.Type()), uint8(icmpHdr.Code()), false, 100*time.Millisecond)
+	conn, err := f.forwardICMPPacket(id, icmpData, uint8(icmpHdr.Type()), uint8(icmpHdr.Code()), 100*time.Millisecond)
 	if err != nil {
 		f.logger.Error2("forwarder: Failed to forward ICMP packet for %v: %v", epID(id), err)
 		return true
@@ -58,7 +58,7 @@ func (f *Forwarder) handleICMPEcho(flowID uuid.UUID, id stack.TransportEndpointI
 			defer func() { <-f.pingSemaphore }()
 
 			if f.hasRawICMPAccess {
-				f.handleICMPViaSocket(flowID, id, icmpType, icmpCode, icmpData, rxBytes, false)
+				f.handleICMPViaSocket(flowID, id, icmpType, icmpCode, icmpData, rxBytes)
 			} else {
 				f.handleICMPViaPing(flowID, id, icmpType, icmpCode, icmpData, rxBytes)
 			}
@@ -72,23 +72,18 @@ func (f *Forwarder) handleICMPEcho(flowID uuid.UUID, id stack.TransportEndpointI
 
 // forwardICMPPacket creates a raw ICMP socket and sends the packet, returning the connection.
 // The caller is responsible for closing the returned connection.
-func (f *Forwarder) forwardICMPPacket(id stack.TransportEndpointID, payload []byte, icmpType, icmpCode uint8, v6 bool, timeout time.Duration) (net.PacketConn, error) {
+func (f *Forwarder) forwardICMPPacket(id stack.TransportEndpointID, payload []byte, icmpType, icmpCode uint8, timeout time.Duration) (net.PacketConn, error) {
 	ctx, cancel := context.WithTimeout(f.ctx, timeout)
 	defer cancel()
 
-	network, listenAddr := "ip4:icmp", "0.0.0.0"
-	if v6 {
-		network, listenAddr = "ip6:ipv6-icmp", "::"
-	}
-
 	lc := net.ListenConfig{}
-	conn, err := lc.ListenPacket(ctx, network, listenAddr)
+	conn, err := lc.ListenPacket(ctx, "ip4:icmp", "0.0.0.0")
 	if err != nil {
 		return nil, fmt.Errorf("create ICMP socket: %w", err)
 	}
 
 	dstIP := f.determineDialAddr(id.LocalAddress)
-	dst := &net.IPAddr{IP: dstIP.AsSlice()}
+	dst := &net.IPAddr{IP: dstIP}
 
 	if _, err = conn.WriteTo(payload, dst); err != nil {
 		if closeErr := conn.Close(); closeErr != nil {
@@ -103,11 +98,11 @@ func (f *Forwarder) forwardICMPPacket(id stack.TransportEndpointID, payload []by
 	return conn, nil
 }
 
-// handleICMPViaSocket handles ICMP echo requests using raw sockets for both v4 and v6.
-func (f *Forwarder) handleICMPViaSocket(flowID uuid.UUID, id stack.TransportEndpointID, icmpType, icmpCode uint8, icmpData []byte, rxBytes int, v6 bool) {
+// handleICMPViaSocket handles ICMP echo requests using raw sockets.
+func (f *Forwarder) handleICMPViaSocket(flowID uuid.UUID, id stack.TransportEndpointID, icmpType, icmpCode uint8, icmpData []byte, rxBytes int) {
 	sendTime := time.Now()
 
-	conn, err := f.forwardICMPPacket(id, icmpData, icmpType, icmpCode, v6, 5*time.Second)
+	conn, err := f.forwardICMPPacket(id, icmpData, icmpType, icmpCode, 5*time.Second)
 	if err != nil {
 		f.logger.Error2("forwarder: Failed to send ICMP packet for %v: %v", epID(id), err)
 		return
@@ -118,20 +113,16 @@ func (f *Forwarder) handleICMPViaSocket(flowID uuid.UUID, id stack.TransportEndp
 		}
 	}()
 
-	txBytes := f.handleEchoResponse(conn, id, v6)
+	txBytes := f.handleEchoResponse(conn, id)
 	rtt := time.Since(sendTime).Round(10 * time.Microsecond)
 
-	proto := "ICMP"
-	if v6 {
-		proto = "ICMPv6"
-	}
-	f.logger.Trace5("forwarder: Forwarded %s echo reply %v type %v code %v (rtt=%v, raw socket)",
-		proto, epID(id), icmpType, icmpCode, rtt)
+	f.logger.Trace4("forwarder: Forwarded ICMP echo reply %v type %v code %v (rtt=%v, raw socket)",
+		epID(id), icmpType, icmpCode, rtt)
 
 	f.sendICMPEvent(nftypes.TypeEnd, flowID, id, icmpType, icmpCode, uint64(rxBytes), uint64(txBytes))
 }
 
-func (f *Forwarder) handleEchoResponse(conn net.PacketConn, id stack.TransportEndpointID, v6 bool) int {
+func (f *Forwarder) handleEchoResponse(conn net.PacketConn, id stack.TransportEndpointID) int {
 	if err := conn.SetReadDeadline(time.Now().Add(5 * time.Second)); err != nil {
 		f.logger.Error1("forwarder: Failed to set read deadline for ICMP response: %v", err)
 		return 0
@@ -146,19 +137,6 @@ func (f *Forwarder) handleEchoResponse(conn net.PacketConn, id stack.TransportEn
 		return 0
 	}
 
-	if v6 {
-		// Recompute checksum: the raw socket response has a checksum computed
-		// over the real endpoint addresses, but we inject with overlay addresses.
-		icmpHdr := header.ICMPv6(response[:n])
-		icmpHdr.SetChecksum(0)
-		icmpHdr.SetChecksum(header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
-			Header: icmpHdr,
-			Src:    id.LocalAddress,
-			Dst:    id.RemoteAddress,
-		}))
-		return f.injectICMPv6Reply(id, response[:n])
-	}
-
 	return f.injectICMPReply(id, response[:n])
 }
 
@@ -172,23 +150,19 @@ func (f *Forwarder) sendICMPEvent(typ nftypes.Type, flowID uuid.UUID, id stack.T
 		txPackets = 1
 	}
 
-	srcIp := addrToNetipAddr(id.RemoteAddress)
-	dstIp := addrToNetipAddr(id.LocalAddress)
-
-	proto := nftypes.ICMP
-	if srcIp.Is6() {
-		proto = nftypes.ICMPv6
-	}
+	srcIp := netip.AddrFrom4(id.RemoteAddress.As4())
+	dstIp := netip.AddrFrom4(id.LocalAddress.As4())
 
 	fields := nftypes.EventFields{
 		FlowID:    flowID,
 		Type:      typ,
 		Direction: nftypes.Ingress,
-		Protocol:  proto,
-		SourceIP:  srcIp,
-		DestIP:    dstIp,
-		ICMPType:  icmpType,
-		ICMPCode:  icmpCode,
+		Protocol:  nftypes.ICMP,
+		// TODO: handle ipv6
+		SourceIP: srcIp,
+		DestIP:   dstIp,
+		ICMPType: icmpType,
+		ICMPCode: icmpCode,
 
 		RxBytes:   rxBytes,
 		TxBytes:   txBytes,
@@ -235,164 +209,26 @@ func (f *Forwarder) handleICMPViaPing(flowID uuid.UUID, id stack.TransportEndpoi
 	f.sendICMPEvent(nftypes.TypeEnd, flowID, id, icmpType, icmpCode, uint64(rxBytes), uint64(txBytes))
 }
 
-// handleICMPv6 handles ICMPv6 packets from the network stack.
-func (f *Forwarder) handleICMPv6(id stack.TransportEndpointID, pkt *stack.PacketBuffer) bool {
-	icmpHdr := header.ICMPv6(pkt.TransportHeader().View().AsSlice())
-
-	flowID := uuid.New()
-	f.sendICMPEvent(nftypes.TypeStart, flowID, id, uint8(icmpHdr.Type()), uint8(icmpHdr.Code()), 0, 0)
-
-	if icmpHdr.Type() == header.ICMPv6EchoRequest {
-		return f.handleICMPv6Echo(flowID, id, pkt, uint8(icmpHdr.Type()), uint8(icmpHdr.Code()))
-	}
-
-	// For non-echo types (Destination Unreachable, Packet Too Big, etc), forward without waiting
-	if !f.hasRawICMPv6Access {
-		f.logger.Debug2("forwarder: Cannot handle ICMPv6 type %v without raw socket access for %v", icmpHdr.Type(), epID(id))
-		return false
-	}
-
-	icmpData := stack.PayloadSince(pkt.TransportHeader()).AsSlice()
-	conn, err := f.forwardICMPPacket(id, icmpData, uint8(icmpHdr.Type()), uint8(icmpHdr.Code()), true, 100*time.Millisecond)
-	if err != nil {
-		f.logger.Error2("forwarder: Failed to forward ICMPv6 packet for %v: %v", epID(id), err)
-		return true
-	}
-	if err := conn.Close(); err != nil {
-		f.logger.Debug1("forwarder: Failed to close ICMPv6 socket: %v", err)
-	}
-
-	return true
-}
-
-// handleICMPv6Echo handles ICMPv6 echo requests via raw socket or ping binary fallback.
-func (f *Forwarder) handleICMPv6Echo(flowID uuid.UUID, id stack.TransportEndpointID, pkt *stack.PacketBuffer, icmpType, icmpCode uint8) bool {
-	select {
-	case f.pingSemaphore <- struct{}{}:
-		icmpData := stack.PayloadSince(pkt.TransportHeader()).ToSlice()
-		rxBytes := pkt.Size()
-
-		go func() {
-			defer func() { <-f.pingSemaphore }()
-
-			if f.hasRawICMPv6Access {
-				f.handleICMPViaSocket(flowID, id, icmpType, icmpCode, icmpData, rxBytes, true)
-			} else {
-				f.handleICMPv6ViaPing(flowID, id, icmpType, icmpCode, icmpData, rxBytes)
-			}
-		}()
-	default:
-		f.logger.Debug3("forwarder: ICMPv6 rate limit exceeded for %v type %v code %v", epID(id), icmpType, icmpCode)
-	}
-	return true
-}
-
-// handleICMPv6ViaPing uses the system ping6 binary for ICMPv6 echo.
-func (f *Forwarder) handleICMPv6ViaPing(flowID uuid.UUID, id stack.TransportEndpointID, icmpType, icmpCode uint8, icmpData []byte, rxBytes int) {
-	ctx, cancel := context.WithTimeout(f.ctx, 5*time.Second)
-	defer cancel()
-
-	dstIP := f.determineDialAddr(id.LocalAddress)
-	cmd := buildPingCommand(ctx, dstIP, 5*time.Second)
-
-	pingStart := time.Now()
-	if err := cmd.Run(); err != nil {
-		f.logger.Warn4("forwarder: Ping6 failed for %v type %v code %v: %v", epID(id), icmpType, icmpCode, err)
-		return
-	}
-	rtt := time.Since(pingStart).Round(10 * time.Microsecond)
-
-	f.logger.Trace3("forwarder: Forwarded ICMPv6 echo request %v type %v code %v",
-		epID(id), icmpType, icmpCode)
-
-	txBytes := f.synthesizeICMPv6EchoReply(id, icmpData)
-
-	f.logger.Trace4("forwarder: Forwarded ICMPv6 echo reply %v type %v code %v (rtt=%v, ping binary)",
-		epID(id), icmpType, icmpCode, rtt)
-
-	f.sendICMPEvent(nftypes.TypeEnd, flowID, id, icmpType, icmpCode, uint64(rxBytes), uint64(txBytes))
-}
-
-// synthesizeICMPv6EchoReply creates an ICMPv6 echo reply and injects it back.
-func (f *Forwarder) synthesizeICMPv6EchoReply(id stack.TransportEndpointID, icmpData []byte) int {
-	replyICMP := make([]byte, len(icmpData))
-	copy(replyICMP, icmpData)
-
-	replyHdr := header.ICMPv6(replyICMP)
-	replyHdr.SetType(header.ICMPv6EchoReply)
-	replyHdr.SetChecksum(0)
-	// ICMPv6Checksum computes the pseudo-header internally from Src/Dst.
-	// Header contains the full ICMP message, so PayloadCsum/PayloadLen are zero.
-	replyHdr.SetChecksum(header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
-		Header: replyHdr,
-		Src:    id.LocalAddress,
-		Dst:    id.RemoteAddress,
-	}))
-
-	return f.injectICMPv6Reply(id, replyICMP)
-}
-
-// injectICMPv6Reply wraps an ICMPv6 payload in an IPv6 header and sends to the peer.
-func (f *Forwarder) injectICMPv6Reply(id stack.TransportEndpointID, icmpPayload []byte) int {
-	ipHdr := make([]byte, header.IPv6MinimumSize)
-	ip := header.IPv6(ipHdr)
-	ip.Encode(&header.IPv6Fields{
-		PayloadLength:     uint16(len(icmpPayload)),
-		TransportProtocol: header.ICMPv6ProtocolNumber,
-		HopLimit:          64,
-		SrcAddr:           id.LocalAddress,
-		DstAddr:           id.RemoteAddress,
-	})
-
-	fullPacket := make([]byte, 0, len(ipHdr)+len(icmpPayload))
-	fullPacket = append(fullPacket, ipHdr...)
-	fullPacket = append(fullPacket, icmpPayload...)
-
-	if err := f.endpoint.device.CreateOutboundPacket(fullPacket, id.RemoteAddress.AsSlice()); err != nil {
-		f.logger.Error1("forwarder: Failed to send ICMPv6 reply to peer: %v", err)
-		return 0
-	}
-
-	return len(fullPacket)
-}
-
-const (
-	pingBin  = "ping"
-	ping6Bin = "ping6"
-)
-
 // buildPingCommand creates a platform-specific ping command.
-// Most platforms auto-detect IPv6 from raw addresses. macOS/iOS/OpenBSD require ping6.
-func buildPingCommand(ctx context.Context, target netip.Addr, timeout time.Duration) *exec.Cmd {
+func buildPingCommand(ctx context.Context, target net.IP, timeout time.Duration) *exec.Cmd {
 	timeoutSec := int(timeout.Seconds())
 	if timeoutSec < 1 {
 		timeoutSec = 1
 	}
 
-	isV6 := target.Is6()
-	timeoutStr := fmt.Sprintf("%d", timeoutSec)
-
 	switch runtime.GOOS {
 	case "linux", "android":
-		return exec.CommandContext(ctx, pingBin, "-c", "1", "-W", timeoutStr, "-q", target.String())
+		return exec.CommandContext(ctx, "ping", "-c", "1", "-W", fmt.Sprintf("%d", timeoutSec), "-q", target.String())
 	case "darwin", "ios":
-		bin := pingBin
-		if isV6 {
-			bin = ping6Bin
-		}
-		return exec.CommandContext(ctx, bin, "-c", "1", "-t", timeoutStr, "-q", target.String())
+		return exec.CommandContext(ctx, "ping", "-c", "1", "-t", fmt.Sprintf("%d", timeoutSec), "-q", target.String())
 	case "freebsd":
-		return exec.CommandContext(ctx, pingBin, "-c", "1", "-t", timeoutStr, target.String())
+		return exec.CommandContext(ctx, "ping", "-c", "1", "-t", fmt.Sprintf("%d", timeoutSec), target.String())
 	case "openbsd", "netbsd":
-		bin := pingBin
-		if isV6 {
-			bin = ping6Bin
-		}
-		return exec.CommandContext(ctx, bin, "-c", "1", "-w", timeoutStr, target.String())
+		return exec.CommandContext(ctx, "ping", "-c", "1", "-w", fmt.Sprintf("%d", timeoutSec), target.String())
 	case "windows":
-		return exec.CommandContext(ctx, pingBin, "-n", "1", "-w", fmt.Sprintf("%d", timeoutSec*1000), target.String())
+		return exec.CommandContext(ctx, "ping", "-n", "1", "-w", fmt.Sprintf("%d", timeoutSec*1000), target.String())
 	default:
-		return exec.CommandContext(ctx, pingBin, "-c", "1", target.String())
+		return exec.CommandContext(ctx, "ping", "-c", "1", target.String())
 	}
 }
 

client/firewall/uspfilter/forwarder/tcp.go

@@ -2,9 +2,10 @@ package forwarder
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"net"
-	"strconv"
+	"net/netip"
 	"sync"
 
 	"github.com/google/uuid"
@@ -32,7 +33,7 @@ func (f *Forwarder) handleTCP(r *tcp.ForwarderRequest) {
 		}
 	}()
 
-	dialAddr := net.JoinHostPort(f.determineDialAddr(id.LocalAddress).String(), strconv.Itoa(int(id.LocalPort)))
+	dialAddr := fmt.Sprintf("%s:%d", f.determineDialAddr(id.LocalAddress), id.LocalPort)
 
 	outConn, err := (&net.Dialer{}).DialContext(f.ctx, "tcp", dialAddr)
 	if err != nil {
@@ -132,14 +133,15 @@ func (f *Forwarder) proxyTCP(id stack.TransportEndpointID, inConn *gonet.TCPConn
 }
 
 func (f *Forwarder) sendTCPEvent(typ nftypes.Type, flowID uuid.UUID, id stack.TransportEndpointID, rxBytes, txBytes, rxPackets, txPackets uint64) {
-	srcIp := addrToNetipAddr(id.RemoteAddress)
-	dstIp := addrToNetipAddr(id.LocalAddress)
+	srcIp := netip.AddrFrom4(id.RemoteAddress.As4())
+	dstIp := netip.AddrFrom4(id.LocalAddress.As4())
 
 	fields := nftypes.EventFields{
-		FlowID:     flowID,
-		Type:       typ,
-		Direction:  nftypes.Ingress,
-		Protocol:   nftypes.TCP,
+		FlowID:    flowID,
+		Type:      typ,
+		Direction: nftypes.Ingress,
+		Protocol:  nftypes.TCP,
+		// TODO: handle ipv6
 		SourceIP:   srcIp,
 		DestIP:     dstIp,
 		SourcePort: id.RemotePort,

client/firewall/uspfilter/forwarder/udp.go

@@ -6,7 +6,7 @@ import (
 	"fmt"
 	"io"
 	"net"
-	"strconv"
+	"net/netip"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -158,7 +158,7 @@ func (f *Forwarder) handleUDP(r *udp.ForwarderRequest) bool {
 		}
 	}()
 
-	dstAddr := net.JoinHostPort(f.determineDialAddr(id.LocalAddress).String(), strconv.Itoa(int(id.LocalPort)))
+	dstAddr := fmt.Sprintf("%s:%d", f.determineDialAddr(id.LocalAddress), id.LocalPort)
 	outConn, err := (&net.Dialer{}).DialContext(f.ctx, "udp", dstAddr)
 	if err != nil {
 		f.logger.Debug2("forwarder: UDP dial error for %v: %v", epID(id), err)
@@ -276,14 +276,15 @@ func (f *Forwarder) proxyUDP(ctx context.Context, pConn *udpPacketConn, id stack
 
 // sendUDPEvent stores flow events for UDP connections
 func (f *Forwarder) sendUDPEvent(typ nftypes.Type, flowID uuid.UUID, id stack.TransportEndpointID, rxBytes, txBytes, rxPackets, txPackets uint64) {
-	srcIp := addrToNetipAddr(id.RemoteAddress)
-	dstIp := addrToNetipAddr(id.LocalAddress)
+	srcIp := netip.AddrFrom4(id.RemoteAddress.As4())
+	dstIp := netip.AddrFrom4(id.LocalAddress.As4())
 
 	fields := nftypes.EventFields{
-		FlowID:     flowID,
-		Type:       typ,
-		Direction:  nftypes.Ingress,
-		Protocol:   nftypes.UDP,
+		FlowID:    flowID,
+		Type:      typ,
+		Direction: nftypes.Ingress,
+		Protocol:  nftypes.UDP,
+		// TODO: handle ipv6
 		SourceIP:   srcIp,
 		DestIP:     dstIp,
 		SourcePort: id.RemotePort,

client/firewall/uspfilter/hooks_filter.go

@@ -13,6 +13,7 @@ const (
 	ipv4HeaderMinLen = 20
 	ipv4ProtoOffset  = 9
 	ipv4FlagsOffset  = 6
+	ipv4DstOffset    = 16
 	ipProtoUDP       = 17
 	ipProtoTCP       = 6
 	ipv4FragOffMask  = 0x1fff

client/firewall/uspfilter/localip.go

@@ -4,32 +4,89 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
-	"sync/atomic"
+	"sync"
 
 	log "github.com/sirupsen/logrus"
 
 	"github.com/netbirdio/netbird/client/firewall/uspfilter/common"
 )
 
-// localIPSnapshot is an immutable snapshot of local IP addresses, swapped
-// atomically so reads are lock-free.
-type localIPSnapshot struct {
-	ips map[netip.Addr]struct{}
+type localIPManager struct {
+	mu sync.RWMutex
+
+	// fixed-size high array for upper byte of a IPv4 address
+	ipv4Bitmap [256]*ipv4LowBitmap
 }
 
-type localIPManager struct {
-	snapshot atomic.Pointer[localIPSnapshot]
+// ipv4LowBitmap is a map for the low 16 bits of a IPv4 address
+type ipv4LowBitmap struct {
+	bitmap [8192]uint32
 }
 
 func newLocalIPManager() *localIPManager {
-	m := &localIPManager{}
-	m.snapshot.Store(&localIPSnapshot{
-		ips: make(map[netip.Addr]struct{}),
-	})
-	return m
+	return &localIPManager{}
 }
 
-func processInterface(iface net.Interface, ips map[netip.Addr]struct{}, addresses *[]netip.Addr) {
+func (m *localIPManager) setBitmapBit(ip net.IP) {
+	ipv4 := ip.To4()
+	if ipv4 == nil {
+		return
+	}
+	high := uint16(ipv4[0])
+	low := (uint16(ipv4[1]) << 8) | (uint16(ipv4[2]) << 4) | uint16(ipv4[3])
+
+	index := low / 32
+	bit := low % 32
+
+	if m.ipv4Bitmap[high] == nil {
+		m.ipv4Bitmap[high] = &ipv4LowBitmap{}
+	}
+
+	m.ipv4Bitmap[high].bitmap[index] |= 1 << bit
+}
+
+func (m *localIPManager) setBitInBitmap(ip netip.Addr, bitmap *[256]*ipv4LowBitmap, ipv4Set map[netip.Addr]struct{}, ipv4Addresses *[]netip.Addr) {
+	if !ip.Is4() {
+		return
+	}
+	ipv4 := ip.AsSlice()
+
+	high := uint16(ipv4[0])
+	low := (uint16(ipv4[1]) << 8) | (uint16(ipv4[2]) << 4) | uint16(ipv4[3])
+
+	if bitmap[high] == nil {
+		bitmap[high] = &ipv4LowBitmap{}
+	}
+
+	index := low / 32
+	bit := low % 32
+	bitmap[high].bitmap[index] |= 1 << bit
+
+	if _, exists := ipv4Set[ip]; !exists {
+		ipv4Set[ip] = struct{}{}
+		*ipv4Addresses = append(*ipv4Addresses, ip)
+	}
+}
+
+func (m *localIPManager) checkBitmapBit(ip []byte) bool {
+	high := uint16(ip[0])
+	low := (uint16(ip[1]) << 8) | (uint16(ip[2]) << 4) | uint16(ip[3])
+
+	if m.ipv4Bitmap[high] == nil {
+		return false
+	}
+
+	index := low / 32
+	bit := low % 32
+	return (m.ipv4Bitmap[high].bitmap[index] & (1 << bit)) != 0
+}
+
+func (m *localIPManager) processIP(ip netip.Addr, bitmap *[256]*ipv4LowBitmap, ipv4Set map[netip.Addr]struct{}, ipv4Addresses *[]netip.Addr) error {
+	m.setBitInBitmap(ip, bitmap, ipv4Set, ipv4Addresses)
+	return nil
+}
+
+func (m *localIPManager) processInterface(iface net.Interface, bitmap *[256]*ipv4LowBitmap, ipv4Set map[netip.Addr]struct{}, ipv4Addresses *[]netip.Addr) {
 	addrs, err := iface.Addrs()
 	if err != nil {
 		log.Debugf("get addresses for interface %s failed: %v", iface.Name, err)
@@ -47,19 +104,18 @@ func processInterface(iface net.Interface, ips map[netip.Addr]struct{}, addresse
 			continue
 		}
 
-		parsed, ok := netip.AddrFromSlice(ip)
+		addr, ok := netip.AddrFromSlice(ip)
 		if !ok {
 			log.Warnf("invalid IP address %s in interface %s", ip.String(), iface.Name)
 			continue
 		}
 
-		parsed = parsed.Unmap()
-		ips[parsed] = struct{}{}
-		*addresses = append(*addresses, parsed)
+		if err := m.processIP(addr.Unmap(), bitmap, ipv4Set, ipv4Addresses); err != nil {
+			log.Debugf("process IP failed: %v", err)
+		}
 	}
 }
 
-// UpdateLocalIPs rebuilds the local IP snapshot and swaps it in atomically.
 func (m *localIPManager) UpdateLocalIPs(iface common.IFaceMapper) (err error) {
 	defer func() {
 		if r := recover(); r != nil {
@@ -67,20 +123,20 @@ func (m *localIPManager) UpdateLocalIPs(iface common.IFaceMapper) (err error) {
 		}
 	}()
 
-	ips := make(map[netip.Addr]struct{})
-	var addresses []netip.Addr
+	var newIPv4Bitmap [256]*ipv4LowBitmap
+	ipv4Set := make(map[netip.Addr]struct{})
+	var ipv4Addresses []netip.Addr
 
-	// loopback
-	ips[netip.AddrFrom4([4]byte{127, 0, 0, 1})] = struct{}{}
-	ips[netip.IPv6Loopback()] = struct{}{}
+	// 127.0.0.0/8
+	newIPv4Bitmap[127] = &ipv4LowBitmap{}
+	for i := 0; i < 8192; i++ {
+		// #nosec G602 -- bitmap is defined as [8192]uint32, loop range is correct
+		newIPv4Bitmap[127].bitmap[i] = 0xFFFFFFFF
+	}
 
 	if iface != nil {
-		ip := iface.Address().IP
-		ips[ip] = struct{}{}
-		addresses = append(addresses, ip)
-		if v6 := iface.Address().IPv6; v6.IsValid() {
-			ips[v6] = struct{}{}
-			addresses = append(addresses, v6)
+		if err := m.processIP(iface.Address().IP, &newIPv4Bitmap, ipv4Set, &ipv4Addresses); err != nil {
+			return err
 		}
 	}
 
@@ -91,24 +147,25 @@ func (m *localIPManager) UpdateLocalIPs(iface common.IFaceMapper) (err error) {
 		// TODO: filter out down interfaces (net.FlagUp). Also handle the reverse
 		// case where an interface comes up between refreshes.
 		for _, intf := range interfaces {
-			processInterface(intf, ips, &addresses)
+			m.processInterface(intf, &newIPv4Bitmap, ipv4Set, &ipv4Addresses)
 		}
 	}
 
-	m.snapshot.Store(&localIPSnapshot{ips: ips})
+	m.mu.Lock()
+	m.ipv4Bitmap = newIPv4Bitmap
+	m.mu.Unlock()
 
-	log.Debugf("Local IP addresses: %v", addresses)
+	log.Debugf("Local IPv4 addresses: %v", ipv4Addresses)
 	return nil
 }
 
-// IsLocalIP checks if the given IP is a local address. Lock-free on the read path.
 func (m *localIPManager) IsLocalIP(ip netip.Addr) bool {
-	s := m.snapshot.Load()
-
-	if ip.Is4() && ip.As4()[0] == 127 {
-		return true
+	if !ip.Is4() {
+		return false
 	}
 
-	_, found := s.ips[ip]
-	return found
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	return m.checkBitmapBit(ip.AsSlice())
 }

client/firewall/uspfilter/localip_bench_test.go

@@ -1,72 +0,0 @@
-package uspfilter
-
-import (
-	"net/netip"
-	"testing"
-
-	"github.com/netbirdio/netbird/client/iface/wgaddr"
-)
-
-func setupManager(b *testing.B) *localIPManager {
-	b.Helper()
-	m := newLocalIPManager()
-	mock := &IFaceMock{
-		AddressFunc: func() wgaddr.Address {
-			return wgaddr.Address{
-				IP:      netip.MustParseAddr("100.64.0.1"),
-				Network: netip.MustParsePrefix("100.64.0.0/16"),
-				IPv6:    netip.MustParseAddr("fd00::1"),
-				IPv6Net: netip.MustParsePrefix("fd00::/64"),
-			}
-		},
-	}
-	if err := m.UpdateLocalIPs(mock); err != nil {
-		b.Fatalf("UpdateLocalIPs: %v", err)
-	}
-	return m
-}
-
-func BenchmarkIsLocalIP_v4_hit(b *testing.B) {
-	m := setupManager(b)
-	ip := netip.MustParseAddr("100.64.0.1")
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		m.IsLocalIP(ip)
-	}
-}
-
-func BenchmarkIsLocalIP_v4_miss(b *testing.B) {
-	m := setupManager(b)
-	ip := netip.MustParseAddr("8.8.8.8")
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		m.IsLocalIP(ip)
-	}
-}
-
-func BenchmarkIsLocalIP_v6_hit(b *testing.B) {
-	m := setupManager(b)
-	ip := netip.MustParseAddr("fd00::1")
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		m.IsLocalIP(ip)
-	}
-}
-
-func BenchmarkIsLocalIP_v6_miss(b *testing.B) {
-	m := setupManager(b)
-	ip := netip.MustParseAddr("2001:db8::1")
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		m.IsLocalIP(ip)
-	}
-}
-
-func BenchmarkIsLocalIP_loopback(b *testing.B) {
-	m := setupManager(b)
-	ip := netip.MustParseAddr("127.0.0.1")
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		m.IsLocalIP(ip)
-	}
-}

client/firewall/uspfilter/localip_test.go

@@ -72,45 +72,14 @@ func TestLocalIPManager(t *testing.T) {
 			expected: false,
 		},
 		{
-			name: "IPv6 address matches",
+			name: "IPv6 address",
 			setupAddr: wgaddr.Address{
-				IP:      netip.MustParseAddr("100.64.0.1"),
-				Network: netip.MustParsePrefix("100.64.0.0/16"),
-				IPv6:    netip.MustParseAddr("fd00::1"),
-				IPv6Net: netip.MustParsePrefix("fd00::/64"),
-			},
-			testIP:   netip.MustParseAddr("fd00::1"),
-			expected: true,
-		},
-		{
-			name: "IPv6 address does not match",
-			setupAddr: wgaddr.Address{
-				IP:      netip.MustParseAddr("100.64.0.1"),
-				Network: netip.MustParsePrefix("100.64.0.0/16"),
-				IPv6:    netip.MustParseAddr("fd00::1"),
-				IPv6Net: netip.MustParsePrefix("fd00::/64"),
-			},
-			testIP:   netip.MustParseAddr("fd00::99"),
-			expected: false,
-		},
-		{
-			name: "No aliasing between similar IPs",
-			setupAddr: wgaddr.Address{
-				IP:      netip.MustParseAddr("192.168.1.1"),
+				IP:      netip.MustParseAddr("fe80::1"),
 				Network: netip.MustParsePrefix("192.168.1.0/24"),
 			},
-			testIP:   netip.MustParseAddr("192.168.0.17"),
+			testIP:   netip.MustParseAddr("fe80::1"),
 			expected: false,
 		},
-		{
-			name: "IPv6 loopback",
-			setupAddr: wgaddr.Address{
-				IP:      netip.MustParseAddr("100.64.0.1"),
-				Network: netip.MustParsePrefix("100.64.0.0/16"),
-			},
-			testIP:   netip.MustParseAddr("::1"),
-			expected: true,
-		},
 	}
 
 	for _, tt := range tests {
@@ -202,3 +171,90 @@ func TestLocalIPManager_AllInterfaces(t *testing.T) {
 		})
 	}
 }
+
+// MapImplementation is a version using map[string]struct{}
+type MapImplementation struct {
+	localIPs map[string]struct{}
+}
+
+func BenchmarkIPChecks(b *testing.B) {
+	interfaces := make([]net.IP, 16)
+	for i := range interfaces {
+		interfaces[i] = net.IPv4(10, 0, byte(i>>8), byte(i))
+	}
+
+	// Setup bitmap
+	bitmapManager := newLocalIPManager()
+	for _, ip := range interfaces[:8] { // Add half of IPs
+		bitmapManager.setBitmapBit(ip)
+	}
+
+	// Setup map version
+	mapManager := &MapImplementation{
+		localIPs: make(map[string]struct{}),
+	}
+	for _, ip := range interfaces[:8] {
+		mapManager.localIPs[ip.String()] = struct{}{}
+	}
+
+	b.Run("Bitmap_Hit", func(b *testing.B) {
+		ip := interfaces[4]
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			bitmapManager.checkBitmapBit(ip)
+		}
+	})
+
+	b.Run("Bitmap_Miss", func(b *testing.B) {
+		ip := interfaces[12]
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			bitmapManager.checkBitmapBit(ip)
+		}
+	})
+
+	b.Run("Map_Hit", func(b *testing.B) {
+		ip := interfaces[4]
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			// nolint:gosimple
+			_ = mapManager.localIPs[ip.String()]
+		}
+	})
+
+	b.Run("Map_Miss", func(b *testing.B) {
+		ip := interfaces[12]
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			// nolint:gosimple
+			_ = mapManager.localIPs[ip.String()]
+		}
+	})
+}
+
+func BenchmarkWGPosition(b *testing.B) {
+	wgIP := net.ParseIP("10.10.0.1")
+
+	// Create two managers - one checks WG IP first, other checks it last
+	b.Run("WG_First", func(b *testing.B) {
+		bm := newLocalIPManager()
+		bm.setBitmapBit(wgIP)
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			bm.checkBitmapBit(wgIP)
+		}
+	})
+
+	b.Run("WG_Last", func(b *testing.B) {
+		bm := newLocalIPManager()
+		// Fill with other IPs first
+		for i := 0; i < 15; i++ {
+			bm.setBitmapBit(net.IPv4(10, 0, byte(i>>8), byte(i)))
+		}
+		bm.setBitmapBit(wgIP) // Add WG IP last
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			bm.checkBitmapBit(wgIP)
+		}
+	})
+}

client/firewall/uspfilter/nat.go

@@ -13,6 +13,8 @@ import (
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 )
 
+var ErrIPv4Only = errors.New("only IPv4 is supported for DNAT")
+
 var (
 	errInvalidIPHeaderLength = errors.New("invalid IP header length")
 )
@@ -23,33 +25,10 @@ const (
 	destinationPortOffset = 2
 
 	// IP address offsets in IPv4 header
-	ipv4SrcOffset = 12
-	ipv4DstOffset = 16
-
-	// IP address offsets in IPv6 header
-	ipv6SrcOffset = 8
-	ipv6DstOffset = 24
-
-	// IPv6 fixed header length
-	ipv6HeaderLen = 40
+	sourceIPOffset      = 12
+	destinationIPOffset = 16
 )
 
-// ipHeaderLen returns the IP header length based on the decoded layer type.
-func ipHeaderLen(d *decoder) (int, error) {
-	switch d.decoded[0] {
-	case layers.LayerTypeIPv4:
-		n := int(d.ip4.IHL) * 4
-		if n < 20 {
-			return 0, errInvalidIPHeaderLength
-		}
-		return n, nil
-	case layers.LayerTypeIPv6:
-		return ipv6HeaderLen, nil
-	default:
-		return 0, fmt.Errorf("unknown IP layer: %v", d.decoded[0])
-	}
-}
-
 // ipv4Checksum calculates IPv4 header checksum.
 func ipv4Checksum(header []byte) uint16 {
 	if len(header) < 20 {
@@ -255,13 +234,14 @@ func (m *Manager) translateOutboundDNAT(packetData []byte, d *decoder) bool {
 		return false
 	}
 
-	_, dstIP := extractPacketIPs(packetData, d)
+	dstIP := netip.AddrFrom4([4]byte{packetData[16], packetData[17], packetData[18], packetData[19]})
+
 	translatedIP, exists := m.getDNATTranslation(dstIP)
 	if !exists {
 		return false
 	}
 
-	if err := m.rewritePacketIP(packetData, d, translatedIP, false); err != nil {
+	if err := m.rewritePacketIP(packetData, d, translatedIP, destinationIPOffset); err != nil {
 		m.logger.Error1("failed to rewrite packet destination: %v", err)
 		return false
 	}
@@ -276,13 +256,14 @@ func (m *Manager) translateInboundReverse(packetData []byte, d *decoder) bool {
 		return false
 	}
 
-	srcIP, _ := extractPacketIPs(packetData, d)
+	srcIP := netip.AddrFrom4([4]byte{packetData[12], packetData[13], packetData[14], packetData[15]})
+
 	originalIP, exists := m.findReverseDNATMapping(srcIP)
 	if !exists {
 		return false
 	}
 
-	if err := m.rewritePacketIP(packetData, d, originalIP, true); err != nil {
+	if err := m.rewritePacketIP(packetData, d, originalIP, sourceIPOffset); err != nil {
 		m.logger.Error1("failed to rewrite packet source: %v", err)
 		return false
 	}
@@ -291,96 +272,38 @@ func (m *Manager) translateInboundReverse(packetData []byte, d *decoder) bool {
 	return true
 }
 
-// extractPacketIPs extracts src and dst IP addresses directly from raw packet bytes.
-func extractPacketIPs(packetData []byte, d *decoder) (src, dst netip.Addr) {
-	switch d.decoded[0] {
-	case layers.LayerTypeIPv4:
-		src = netip.AddrFrom4([4]byte{packetData[ipv4SrcOffset], packetData[ipv4SrcOffset+1], packetData[ipv4SrcOffset+2], packetData[ipv4SrcOffset+3]})
-		dst = netip.AddrFrom4([4]byte{packetData[ipv4DstOffset], packetData[ipv4DstOffset+1], packetData[ipv4DstOffset+2], packetData[ipv4DstOffset+3]})
-	case layers.LayerTypeIPv6:
-		src = netip.AddrFrom16([16]byte(packetData[ipv6SrcOffset : ipv6SrcOffset+16]))
-		dst = netip.AddrFrom16([16]byte(packetData[ipv6DstOffset : ipv6DstOffset+16]))
-	}
-	return src, dst
-}
-
-// rewritePacketIP replaces a source (isSource=true) or destination IP address in the packet and updates checksums.
-func (m *Manager) rewritePacketIP(packetData []byte, d *decoder, newIP netip.Addr, isSource bool) error {
-	hdrLen, err := ipHeaderLen(d)
-	if err != nil {
-		return err
-	}
-
-	switch d.decoded[0] {
-	case layers.LayerTypeIPv4:
-		return m.rewriteIPv4(packetData, d, newIP, hdrLen, isSource)
-	case layers.LayerTypeIPv6:
-		return m.rewriteIPv6(packetData, d, newIP, hdrLen, isSource)
-	default:
-		return fmt.Errorf("unknown IP layer: %v", d.decoded[0])
-	}
-}
-
-func (m *Manager) rewriteIPv4(packetData []byte, d *decoder, newIP netip.Addr, hdrLen int, isSource bool) error {
+// rewritePacketIP replaces an IP address (source or destination) in the packet and updates checksums.
+func (m *Manager) rewritePacketIP(packetData []byte, d *decoder, newIP netip.Addr, ipOffset int) error {
 	if !newIP.Is4() {
-		return fmt.Errorf("cannot write IPv6 address into IPv4 packet")
-	}
-
-	offset := ipv4DstOffset
-	if isSource {
-		offset = ipv4SrcOffset
+		return ErrIPv4Only
 	}
 
 	var oldIP [4]byte
-	copy(oldIP[:], packetData[offset:offset+4])
+	copy(oldIP[:], packetData[ipOffset:ipOffset+4])
 	newIPBytes := newIP.As4()
-	copy(packetData[offset:offset+4], newIPBytes[:])
 
-	// Recalculate IPv4 header checksum
+	copy(packetData[ipOffset:ipOffset+4], newIPBytes[:])
+
+	ipHeaderLen := int(d.ip4.IHL) * 4
+	if ipHeaderLen < 20 || ipHeaderLen > len(packetData) {
+		return errInvalidIPHeaderLength
+	}
+
 	binary.BigEndian.PutUint16(packetData[10:12], 0)
-	binary.BigEndian.PutUint16(packetData[10:12], ipv4Checksum(packetData[:hdrLen]))
+	ipChecksum := ipv4Checksum(packetData[:ipHeaderLen])
+	binary.BigEndian.PutUint16(packetData[10:12], ipChecksum)
 
-	// Update transport checksums incrementally
 	if len(d.decoded) > 1 {
 		switch d.decoded[1] {
 		case layers.LayerTypeTCP:
-			m.updateTCPChecksum(packetData, hdrLen, oldIP[:], newIPBytes[:])
+			m.updateTCPChecksum(packetData, ipHeaderLen, oldIP[:], newIPBytes[:])
 		case layers.LayerTypeUDP:
-			m.updateUDPChecksum(packetData, hdrLen, oldIP[:], newIPBytes[:])
+			m.updateUDPChecksum(packetData, ipHeaderLen, oldIP[:], newIPBytes[:])
 		case layers.LayerTypeICMPv4:
-			m.updateICMPChecksum(packetData, hdrLen)
+			m.updateICMPChecksum(packetData, ipHeaderLen)
 		}
 	}
-	return nil
-}
 
-func (m *Manager) rewriteIPv6(packetData []byte, d *decoder, newIP netip.Addr, hdrLen int, isSource bool) error {
-	if !newIP.Is6() {
-		return fmt.Errorf("cannot write IPv4 address into IPv6 packet")
-	}
-
-	offset := ipv6DstOffset
-	if isSource {
-		offset = ipv6SrcOffset
-	}
-
-	var oldIP [16]byte
-	copy(oldIP[:], packetData[offset:offset+16])
-	newIPBytes := newIP.As16()
-	copy(packetData[offset:offset+16], newIPBytes[:])
-
-	// IPv6 has no header checksum, only update transport checksums
-	if len(d.decoded) > 1 {
-		switch d.decoded[1] {
-		case layers.LayerTypeTCP:
-			m.updateTCPChecksum(packetData, hdrLen, oldIP[:], newIPBytes[:])
-		case layers.LayerTypeUDP:
-			m.updateUDPChecksum(packetData, hdrLen, oldIP[:], newIPBytes[:])
-		case layers.LayerTypeICMPv6:
-			// ICMPv6 checksum includes pseudo-header with addresses, use incremental update
-			m.updateICMPv6Checksum(packetData, hdrLen, oldIP[:], newIPBytes[:])
-		}
-	}
 	return nil
 }
 
@@ -428,20 +351,6 @@ func (m *Manager) updateICMPChecksum(packetData []byte, ipHeaderLen int) {
 	binary.BigEndian.PutUint16(icmpData[2:4], checksum)
 }
 
-// updateICMPv6Checksum updates ICMPv6 checksum after address change.
-// ICMPv6 uses a pseudo-header (like TCP/UDP), so incremental update applies.
-func (m *Manager) updateICMPv6Checksum(packetData []byte, ipHeaderLen int, oldIP, newIP []byte) {
-	icmpStart := ipHeaderLen
-	if len(packetData) < icmpStart+4 {
-		return
-	}
-
-	checksumOffset := icmpStart + 2
-	oldChecksum := binary.BigEndian.Uint16(packetData[checksumOffset : checksumOffset+2])
-	newChecksum := incrementalUpdate(oldChecksum, oldIP, newIP)
-	binary.BigEndian.PutUint16(packetData[checksumOffset:checksumOffset+2], newChecksum)
-}
-
 // incrementalUpdate performs incremental checksum update per RFC 1624.
 func incrementalUpdate(oldChecksum uint16, oldBytes, newBytes []byte) uint16 {
 	sum := uint32(^oldChecksum)
@@ -494,14 +403,14 @@ func (m *Manager) DeleteDNATRule(rule firewall.Rule) error {
 }
 
 // addPortRedirection adds a port redirection rule.
-func (m *Manager) addPortRedirection(targetIP netip.Addr, protocol gopacket.LayerType, originalPort, translatedPort uint16) error {
+func (m *Manager) addPortRedirection(targetIP netip.Addr, protocol gopacket.LayerType, sourcePort, targetPort uint16) error {
 	m.portDNATMutex.Lock()
 	defer m.portDNATMutex.Unlock()
 
 	rule := portDNATRule{
 		protocol:   protocol,
-		origPort:   originalPort,
-		targetPort: translatedPort,
+		origPort:   sourcePort,
+		targetPort: targetPort,
 		targetIP:   targetIP,
 	}
 
@@ -513,7 +422,7 @@ func (m *Manager) addPortRedirection(targetIP netip.Addr, protocol gopacket.Laye
 
 // AddInboundDNAT adds an inbound DNAT rule redirecting traffic from NetBird peers to local services.
 // TODO: also delegate to nativeFirewall when available for kernel WG mode
-func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	var layerType gopacket.LayerType
 	switch protocol {
 	case firewall.ProtocolTCP:
@@ -524,16 +433,16 @@ func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protoco
 		return fmt.Errorf("unsupported protocol: %s", protocol)
 	}
 
-	return m.addPortRedirection(localAddr, layerType, originalPort, translatedPort)
+	return m.addPortRedirection(localAddr, layerType, sourcePort, targetPort)
 }
 
 // removePortRedirection removes a port redirection rule.
-func (m *Manager) removePortRedirection(targetIP netip.Addr, protocol gopacket.LayerType, originalPort, translatedPort uint16) error {
+func (m *Manager) removePortRedirection(targetIP netip.Addr, protocol gopacket.LayerType, sourcePort, targetPort uint16) error {
 	m.portDNATMutex.Lock()
 	defer m.portDNATMutex.Unlock()
 
 	m.portDNATRules = slices.DeleteFunc(m.portDNATRules, func(rule portDNATRule) bool {
-		return rule.protocol == protocol && rule.origPort == originalPort && rule.targetPort == translatedPort && rule.targetIP.Compare(targetIP) == 0
+		return rule.protocol == protocol && rule.origPort == sourcePort && rule.targetPort == targetPort && rule.targetIP.Compare(targetIP) == 0
 	})
 
 	if len(m.portDNATRules) == 0 {
@@ -544,7 +453,7 @@ func (m *Manager) removePortRedirection(targetIP netip.Addr, protocol gopacket.L
 }
 
 // RemoveInboundDNAT removes an inbound DNAT rule.
-func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	var layerType gopacket.LayerType
 	switch protocol {
 	case firewall.ProtocolTCP:
@@ -555,23 +464,23 @@ func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Prot
 		return fmt.Errorf("unsupported protocol: %s", protocol)
 	}
 
-	return m.removePortRedirection(localAddr, layerType, originalPort, translatedPort)
+	return m.removePortRedirection(localAddr, layerType, sourcePort, targetPort)
 }
 
 // AddOutputDNAT delegates to the native firewall if available.
-func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	if m.nativeFirewall == nil {
 		return fmt.Errorf("output DNAT not supported without native firewall")
 	}
-	return m.nativeFirewall.AddOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.nativeFirewall.AddOutputDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 // RemoveOutputDNAT delegates to the native firewall if available.
-func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
+func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	if m.nativeFirewall == nil {
 		return nil
 	}
-	return m.nativeFirewall.RemoveOutputDNAT(localAddr, protocol, originalPort, translatedPort)
+	return m.nativeFirewall.RemoveOutputDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
 // translateInboundPortDNAT applies port-specific DNAT translation to inbound packets.
@@ -623,12 +532,12 @@ func (m *Manager) applyPortRule(packetData []byte, d *decoder, srcIP, dstIP neti
 
 // rewriteTCPPort rewrites a TCP port (source or destination) and updates checksum.
 func (m *Manager) rewriteTCPPort(packetData []byte, d *decoder, newPort uint16, portOffset int) error {
-	hdrLen, err := ipHeaderLen(d)
-	if err != nil {
-		return err
+	ipHeaderLen := int(d.ip4.IHL) * 4
+	if ipHeaderLen < 20 || ipHeaderLen > len(packetData) {
+		return errInvalidIPHeaderLength
 	}
 
-	tcpStart := hdrLen
+	tcpStart := ipHeaderLen
 	if len(packetData) < tcpStart+4 {
 		return fmt.Errorf("packet too short for TCP header")
 	}
@@ -654,12 +563,12 @@ func (m *Manager) rewriteTCPPort(packetData []byte, d *decoder, newPort uint16,
 
 // rewriteUDPPort rewrites a UDP port (source or destination) and updates checksum.
 func (m *Manager) rewriteUDPPort(packetData []byte, d *decoder, newPort uint16, portOffset int) error {
-	hdrLen, err := ipHeaderLen(d)
-	if err != nil {
-		return err
+	ipHeaderLen := int(d.ip4.IHL) * 4
+	if ipHeaderLen < 20 || ipHeaderLen > len(packetData) {
+		return errInvalidIPHeaderLength
 	}
 
-	udpStart := hdrLen
+	udpStart := ipHeaderLen
 	if len(packetData) < udpStart+8 {
 		return fmt.Errorf("packet too short for UDP header")
 	}

client/firewall/uspfilter/nat_bench_test.go

@@ -342,17 +342,12 @@ func BenchmarkDNATMemoryAllocations(b *testing.B) {
 
 		// Parse the packet fresh each time to get a clean decoder
 		d := &decoder{decoded: []gopacket.LayerType{}}
-		d.parser4 = gopacket.NewDecodingLayerParser(
+		d.parser = gopacket.NewDecodingLayerParser(
 			layers.LayerTypeIPv4,
 			&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
 		)
-		d.parser4.IgnoreUnsupported = true
-		d.parser6 = gopacket.NewDecodingLayerParser(
-			layers.LayerTypeIPv6,
-			&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
-		)
-		d.parser6.IgnoreUnsupported = true
-		err = d.decodePacket(testPacket)
+		d.parser.IgnoreUnsupported = true
+		err = d.parser.DecodeLayers(testPacket, &d.decoded)
 		assert.NoError(b, err)
 
 		manager.translateOutboundDNAT(testPacket, d)
@@ -376,17 +371,12 @@ func BenchmarkDirectIPExtraction(b *testing.B) {
 	b.Run("decoder_extraction", func(b *testing.B) {
 		// Create decoder once for comparison
 		d := &decoder{decoded: []gopacket.LayerType{}}
-		d.parser4 = gopacket.NewDecodingLayerParser(
+		d.parser = gopacket.NewDecodingLayerParser(
 			layers.LayerTypeIPv4,
 			&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
 		)
-		d.parser4.IgnoreUnsupported = true
-		d.parser6 = gopacket.NewDecodingLayerParser(
-			layers.LayerTypeIPv6,
-			&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
-		)
-		d.parser6.IgnoreUnsupported = true
-		err := d.decodePacket(packet)
+		d.parser.IgnoreUnsupported = true
+		err := d.parser.DecodeLayers(packet, &d.decoded)
 		assert.NoError(b, err)
 
 		for i := 0; i < b.N; i++ {

client/firewall/uspfilter/nat_test.go

@@ -86,18 +86,13 @@ func parsePacket(t testing.TB, packetData []byte) *decoder {
 	d := &decoder{
 		decoded: []gopacket.LayerType{},
 	}
-	d.parser4 = gopacket.NewDecodingLayerParser(
+	d.parser = gopacket.NewDecodingLayerParser(
 		layers.LayerTypeIPv4,
 		&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
 	)
-	d.parser4.IgnoreUnsupported = true
-	d.parser6 = gopacket.NewDecodingLayerParser(
-		layers.LayerTypeIPv6,
-		&d.eth, &d.ip4, &d.ip6, &d.icmp4, &d.icmp6, &d.tcp, &d.udp,
-	)
-	d.parser6.IgnoreUnsupported = true
+	d.parser.IgnoreUnsupported = true
 
-	err := d.decodePacket(packetData)
+	err := d.parser.DecodeLayers(packetData, &d.decoded)
 	require.NoError(t, err)
 	return d
 }

client/firewall/uspfilter/tracer.go

@@ -2,9 +2,7 @@ package uspfilter
 
 import (
 	"fmt"
-	"net"
 	"net/netip"
-	"strconv"
 	"time"
 
 	"github.com/google/gopacket"
@@ -114,13 +112,10 @@ func (t *PacketTrace) AddResultWithForwarder(stage PacketStage, message string,
 }
 
 func (p *PacketBuilder) Build() ([]byte, error) {
-	ipLayer, err := p.buildIPLayer()
-	if err != nil {
-		return nil, err
-	}
-	pktLayers := []gopacket.SerializableLayer{ipLayer}
+	ip := p.buildIPLayer()
+	pktLayers := []gopacket.SerializableLayer{ip}
 
-	transportLayer, err := p.buildTransportLayer(ipLayer)
+	transportLayer, err := p.buildTransportLayer(ip)
 	if err != nil {
 		return nil, err
 	}
@@ -134,43 +129,30 @@ func (p *PacketBuilder) Build() ([]byte, error) {
 	return serializePacket(pktLayers)
 }
 
-func (p *PacketBuilder) buildIPLayer() (gopacket.SerializableLayer, error) {
-	if p.SrcIP.Is4() != p.DstIP.Is4() {
-		return nil, fmt.Errorf("mixed address families: src=%s dst=%s", p.SrcIP, p.DstIP)
-	}
-	proto := getIPProtocolNumber(p.Protocol, p.SrcIP.Is6())
-	if p.SrcIP.Is6() {
-		return &layers.IPv6{
-			Version:    6,
-			HopLimit:   64,
-			NextHeader: proto,
-			SrcIP:      p.SrcIP.AsSlice(),
-			DstIP:      p.DstIP.AsSlice(),
-		}, nil
-	}
+func (p *PacketBuilder) buildIPLayer() *layers.IPv4 {
 	return &layers.IPv4{
 		Version:  4,
 		TTL:      64,
-		Protocol: proto,
+		Protocol: layers.IPProtocol(getIPProtocolNumber(p.Protocol)),
 		SrcIP:    p.SrcIP.AsSlice(),
 		DstIP:    p.DstIP.AsSlice(),
-	}, nil
+	}
 }
 
-func (p *PacketBuilder) buildTransportLayer(ipLayer gopacket.SerializableLayer) ([]gopacket.SerializableLayer, error) {
+func (p *PacketBuilder) buildTransportLayer(ip *layers.IPv4) ([]gopacket.SerializableLayer, error) {
 	switch p.Protocol {
 	case "tcp":
-		return p.buildTCPLayer(ipLayer)
+		return p.buildTCPLayer(ip)
 	case "udp":
-		return p.buildUDPLayer(ipLayer)
+		return p.buildUDPLayer(ip)
 	case "icmp":
-		return p.buildICMPLayer(ipLayer)
+		return p.buildICMPLayer()
 	default:
 		return nil, fmt.Errorf("unsupported protocol: %s", p.Protocol)
 	}
 }
 
-func (p *PacketBuilder) buildTCPLayer(ipLayer gopacket.SerializableLayer) ([]gopacket.SerializableLayer, error) {
+func (p *PacketBuilder) buildTCPLayer(ip *layers.IPv4) ([]gopacket.SerializableLayer, error) {
 	tcp := &layers.TCP{
 		SrcPort: layers.TCPPort(p.SrcPort),
 		DstPort: layers.TCPPort(p.DstPort),
@@ -182,44 +164,24 @@ func (p *PacketBuilder) buildTCPLayer(ipLayer gopacket.SerializableLayer) ([]gop
 		PSH:     p.TCPState != nil && p.TCPState.PSH,
 		URG:     p.TCPState != nil && p.TCPState.URG,
 	}
-	if nl, ok := ipLayer.(gopacket.NetworkLayer); ok {
-		if err := tcp.SetNetworkLayerForChecksum(nl); err != nil {
-			return nil, fmt.Errorf("set network layer for TCP checksum: %w", err)
-		}
+	if err := tcp.SetNetworkLayerForChecksum(ip); err != nil {
+		return nil, fmt.Errorf("set network layer for TCP checksum: %w", err)
 	}
 	return []gopacket.SerializableLayer{tcp}, nil
 }
 
-func (p *PacketBuilder) buildUDPLayer(ipLayer gopacket.SerializableLayer) ([]gopacket.SerializableLayer, error) {
+func (p *PacketBuilder) buildUDPLayer(ip *layers.IPv4) ([]gopacket.SerializableLayer, error) {
 	udp := &layers.UDP{
 		SrcPort: layers.UDPPort(p.SrcPort),
 		DstPort: layers.UDPPort(p.DstPort),
 	}
-	if nl, ok := ipLayer.(gopacket.NetworkLayer); ok {
-		if err := udp.SetNetworkLayerForChecksum(nl); err != nil {
-			return nil, fmt.Errorf("set network layer for UDP checksum: %w", err)
-		}
+	if err := udp.SetNetworkLayerForChecksum(ip); err != nil {
+		return nil, fmt.Errorf("set network layer for UDP checksum: %w", err)
 	}
 	return []gopacket.SerializableLayer{udp}, nil
 }
 
-func (p *PacketBuilder) buildICMPLayer(ipLayer gopacket.SerializableLayer) ([]gopacket.SerializableLayer, error) {
-	if p.SrcIP.Is6() || p.DstIP.Is6() {
-		icmp := &layers.ICMPv6{
-			TypeCode: layers.CreateICMPv6TypeCode(p.ICMPType, p.ICMPCode),
-		}
-		if nl, ok := ipLayer.(gopacket.NetworkLayer); ok {
-			_ = icmp.SetNetworkLayerForChecksum(nl)
-		}
-		if p.ICMPType == layers.ICMPv6TypeEchoRequest || p.ICMPType == layers.ICMPv6TypeEchoReply {
-			echo := &layers.ICMPv6Echo{
-				Identifier: 1,
-				SeqNumber:  1,
-			}
-			return []gopacket.SerializableLayer{icmp, echo}, nil
-		}
-		return []gopacket.SerializableLayer{icmp}, nil
-	}
+func (p *PacketBuilder) buildICMPLayer() ([]gopacket.SerializableLayer, error) {
 	icmp := &layers.ICMPv4{
 		TypeCode: layers.CreateICMPv4TypeCode(p.ICMPType, p.ICMPCode),
 	}
@@ -242,17 +204,14 @@ func serializePacket(layers []gopacket.SerializableLayer) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
-func getIPProtocolNumber(protocol fw.Protocol, isV6 bool) layers.IPProtocol {
+func getIPProtocolNumber(protocol fw.Protocol) int {
 	switch protocol {
 	case fw.ProtocolTCP:
-		return layers.IPProtocolTCP
+		return int(layers.IPProtocolTCP)
 	case fw.ProtocolUDP:
-		return layers.IPProtocolUDP
+		return int(layers.IPProtocolUDP)
 	case fw.ProtocolICMP:
-		if isV6 {
-			return layers.IPProtocolICMPv6
-		}
-		return layers.IPProtocolICMPv4
+		return int(layers.IPProtocolICMPv4)
 	default:
 		return 0
 	}
@@ -275,7 +234,7 @@ func (m *Manager) TracePacket(packetData []byte, direction fw.RuleDirection) *Pa
 	trace := &PacketTrace{Direction: direction}
 
 	// Initial packet decoding
-	if err := d.decodePacket(packetData); err != nil {
+	if err := d.parser.DecodeLayers(packetData, &d.decoded); err != nil {
 		trace.AddResult(StageReceived, fmt.Sprintf("Failed to decode packet: %v", err), false)
 		return trace
 	}
@@ -297,8 +256,6 @@ func (m *Manager) TracePacket(packetData []byte, direction fw.RuleDirection) *Pa
 		trace.DestinationPort = uint16(d.udp.DstPort)
 	case layers.LayerTypeICMPv4:
 		trace.Protocol = "ICMP"
-	case layers.LayerTypeICMPv6:
-		trace.Protocol = "ICMPv6"
 	}
 
 	trace.AddResult(StageReceived, fmt.Sprintf("Received %s packet: %s:%d -> %s:%d",
@@ -362,13 +319,6 @@ func (m *Manager) buildConntrackStateMessage(d *decoder) string {
 			flags&conntrack.TCPFin != 0)
 	case layers.LayerTypeICMPv4:
 		msg += fmt.Sprintf(" (ICMP ID=%d, Seq=%d)", d.icmp4.Id, d.icmp4.Seq)
-	case layers.LayerTypeICMPv6:
-		var id, seq uint16
-		if len(d.icmp6.Payload) >= 4 {
-			id = uint16(d.icmp6.Payload[0])<<8 | uint16(d.icmp6.Payload[1])
-			seq = uint16(d.icmp6.Payload[2])<<8 | uint16(d.icmp6.Payload[3])
-		}
-		msg += fmt.Sprintf(" (ICMPv6 ID=%d, Seq=%d)", id, seq)
 	}
 	return msg
 }
@@ -445,7 +395,7 @@ func (m *Manager) handleRouteACLs(trace *PacketTrace, d *decoder, srcIP, dstIP n
 	trace.AddResult(StageRouteACL, msg, allowed)
 
 	if allowed && m.forwarder.Load() != nil {
-		m.addForwardingResult(trace, "proxy-remote", net.JoinHostPort(dstIP.String(), strconv.Itoa(int(dstPort))), true)
+		m.addForwardingResult(trace, "proxy-remote", fmt.Sprintf("%s:%d", dstIP, dstPort), true)
 	}
 
 	trace.AddResult(StageCompleted, msgProcessingCompleted, allowed)
@@ -465,7 +415,7 @@ func (m *Manager) traceOutbound(packetData []byte, trace *PacketTrace) *PacketTr
 	d := m.decoders.Get().(*decoder)
 	defer m.decoders.Put(d)
 
-	if err := d.decodePacket(packetData); err != nil {
+	if err := d.parser.DecodeLayers(packetData, &d.decoded); err != nil {
 		trace.AddResult(StageCompleted, "Packet dropped - decode error", false)
 		return trace
 	}
@@ -484,7 +434,7 @@ func (m *Manager) traceOutbound(packetData []byte, trace *PacketTrace) *PacketTr
 func (m *Manager) handleInboundDNAT(trace *PacketTrace, packetData []byte, d *decoder, srcIP, dstIP *netip.Addr) bool {
 	portDNATApplied := m.traceInboundPortDNAT(trace, packetData, d)
 	if portDNATApplied {
-		if err := d.decodePacket(packetData); err != nil {
+		if err := d.parser.DecodeLayers(packetData, &d.decoded); err != nil {
 			trace.AddResult(StageInboundPortDNAT, "Failed to re-decode after port DNAT", false)
 			return true
 		}
@@ -494,7 +444,7 @@ func (m *Manager) handleInboundDNAT(trace *PacketTrace, packetData []byte, d *de
 
 	nat1to1Applied := m.traceInbound1to1NAT(trace, packetData, d)
 	if nat1to1Applied {
-		if err := d.decodePacket(packetData); err != nil {
+		if err := d.parser.DecodeLayers(packetData, &d.decoded); err != nil {
 			trace.AddResult(StageInbound1to1NAT, "Failed to re-decode after 1:1 NAT", false)
 			return true
 		}
@@ -559,7 +509,7 @@ func (m *Manager) traceInbound1to1NAT(trace *PacketTrace, packetData []byte, d *
 		return false
 	}
 
-	srcIP, _ := extractPacketIPs(packetData, d)
+	srcIP := netip.AddrFrom4([4]byte{packetData[12], packetData[13], packetData[14], packetData[15]})
 
 	translated := m.translateInboundReverse(packetData, d)
 	if translated {
@@ -589,7 +539,7 @@ func (m *Manager) traceOutbound1to1NAT(trace *PacketTrace, packetData []byte, d
 		return false
 	}
 
-	_, dstIP := extractPacketIPs(packetData, d)
+	dstIP := netip.AddrFrom4([4]byte{packetData[16], packetData[17], packetData[18], packetData[19]})
 
 	translated := m.translateOutboundDNAT(packetData, d)
 	if translated {

client/iface/configurer/usp.go

@@ -119,7 +119,7 @@ func (c *WGUSPConfigurer) UpdatePeer(peerKey string, allowedIps []netip.Prefix,
 		if err != nil {
 			return fmt.Errorf("failed to parse endpoint address: %w", err)
 		}
-		addrPort := netip.AddrPortFrom(addr.Unmap(), uint16(endpoint.Port))
+		addrPort := netip.AddrPortFrom(addr, uint16(endpoint.Port))
 		c.activityRecorder.UpsertAddress(peerKey, addrPort)
 	}
 	return nil

client/iface/device/adapter.go

@@ -2,7 +2,7 @@ package device
 
 // TunAdapter is an interface for create tun device from external service
 type TunAdapter interface {
-	ConfigureInterface(address string, addressV6 string, mtu int, dns string, searchDomains string, routes string) (int, error)
+	ConfigureInterface(address string, mtu int, dns string, searchDomains string, routes string) (int, error)
 	UpdateAddr(address string) error
 	ProtectSocket(fd int32) bool
 }

client/iface/device/device_android.go

@@ -63,7 +63,7 @@ func (t *WGTunDevice) Create(routes []string, dns string, searchDomains []string
 		searchDomainsToString = ""
 	}
 
-	fd, err := t.tunAdapter.ConfigureInterface(t.address.String(), t.address.IPv6String(), int(t.mtu), dns, searchDomainsToString, routesString)
+	fd, err := t.tunAdapter.ConfigureInterface(t.address.String(), int(t.mtu), dns, searchDomainsToString, routesString)
 	if err != nil {
 		log.Errorf("failed to create Android interface: %s", err)
 		return nil, err

client/iface/device/device_darwin.go

@@ -131,32 +131,23 @@ func (t *TunDevice) Device() *device.Device {
 
 // assignAddr Adds IP address to the tunnel interface and network route based on the range provided
 func (t *TunDevice) assignAddr() error {
-	if out, err := exec.Command("ifconfig", t.name, "inet", t.address.IP.String(), t.address.IP.String()).CombinedOutput(); err != nil {
-		return fmt.Errorf("add v4 address: %s: %w", string(out), err)
+	cmd := exec.Command("ifconfig", t.name, "inet", t.address.IP.String(), t.address.IP.String())
+	if out, err := cmd.CombinedOutput(); err != nil {
+		log.Errorf("adding address command '%v' failed with output: %s", cmd.String(), out)
+		return err
 	}
 
-	// Assign a dummy link-local so macOS enables IPv6 on the tun device.
-	// When a real overlay v6 is present, use that instead.
-	v6Addr := "fe80::/64"
-	if t.address.HasIPv6() {
-		v6Addr = t.address.IPv6String()
-	}
-	if out, err := exec.Command("ifconfig", t.name, "inet6", v6Addr).CombinedOutput(); err != nil {
-		log.Warnf("failed to assign IPv6 address %s, continuing v4-only: %s: %v", v6Addr, string(out), err)
-		t.address.ClearIPv6()
+	// dummy ipv6 so routing works
+	cmd = exec.Command("ifconfig", t.name, "inet6", "fe80::/64")
+	if out, err := cmd.CombinedOutput(); err != nil {
+		log.Debugf("adding address command '%v' failed with output: %s", cmd.String(), out)
 	}
 
-	if out, err := exec.Command("route", "add", "-net", t.address.Network.String(), "-interface", t.name).CombinedOutput(); err != nil {
-		return fmt.Errorf("add route %s via %s: %s: %w", t.address.Network, t.name, string(out), err)
+	routeCmd := exec.Command("route", "add", "-net", t.address.Network.String(), "-interface", t.name)
+	if out, err := routeCmd.CombinedOutput(); err != nil {
+		log.Errorf("adding route command '%v' failed with output: %s", routeCmd.String(), out)
+		return err
 	}
-
-	if t.address.HasIPv6() {
-		if out, err := exec.Command("route", "add", "-inet6", "-net", t.address.IPv6Net.String(), "-interface", t.name).CombinedOutput(); err != nil {
-			log.Warnf("failed to add route %s via %s, continuing v4-only: %s: %v", t.address.IPv6Net, t.name, string(out), err)
-			t.address.ClearIPv6()
-		}
-	}
-
 	return nil
 }
 

client/iface/device/device_ios.go

@@ -151,11 +151,8 @@ func (t *TunDevice) MTU() uint16 {
 	return t.mtu
 }
 
-// UpdateAddr updates the device address. On iOS the tunnel is managed by the
-// NetworkExtension, so we only store the new value. The extension picks up the
-// change on the next tunnel reconfiguration.
-func (t *TunDevice) UpdateAddr(addr wgaddr.Address) error {
-	t.address = addr
+func (t *TunDevice) UpdateAddr(_ wgaddr.Address) error {
+	// todo implement
 	return nil
 }
 

client/iface/device/device_kernel_unix.go

@@ -173,7 +173,7 @@ func (t *TunKernelDevice) FilteredDevice() *FilteredDevice {
 
 // assignAddr Adds IP address to the tunnel interface
 func (t *TunKernelDevice) assignAddr() error {
-	return t.link.assignAddr(&t.address)
+	return t.link.assignAddr(t.address)
 }
 
 func (t *TunKernelDevice) GetNet() *netstack.Net {

client/iface/device/device_netstack.go

@@ -3,7 +3,6 @@ package device
 import (
 	"errors"
 	"fmt"
-	"net/netip"
 
 	log "github.com/sirupsen/logrus"
 	"golang.zx2c4.com/wireguard/conn"
@@ -64,12 +63,8 @@ func (t *TunNetstackDevice) create() (WGConfigurer, error) {
 		return nil, fmt.Errorf("last ip: %w", err)
 	}
 
-	addresses := []netip.Addr{t.address.IP}
-	if t.address.HasIPv6() {
-		addresses = append(addresses, t.address.IPv6)
-	}
-	log.Debugf("netstack using addresses: %v", addresses)
-	t.nsTun = nbnetstack.NewNetStackTun(t.listenAddress, addresses, dnsAddr, int(t.mtu))
+	log.Debugf("netstack using address: %s", t.address.IP)
+	t.nsTun = nbnetstack.NewNetStackTun(t.listenAddress, t.address.IP, dnsAddr, int(t.mtu))
 	log.Debugf("netstack using dns address: %s", dnsAddr)
 	tunIface, net, err := t.nsTun.Create()
 	if err != nil {

client/iface/device/device_usp_unix.go

@@ -16,7 +16,7 @@ import (
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 )
 
-type TunDevice struct {
+type USPDevice struct {
 	name    string
 	address wgaddr.Address
 	port    int
@@ -30,10 +30,10 @@ type TunDevice struct {
 	configurer     WGConfigurer
 }
 
-func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind) *TunDevice {
+func NewUSPDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind) *USPDevice {
 	log.Infof("using userspace bind mode")
 
-	return &TunDevice{
+	return &USPDevice{
 		name:    name,
 		address: address,
 		port:    port,
@@ -43,7 +43,7 @@ func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu
 	}
 }
 
-func (t *TunDevice) Create() (WGConfigurer, error) {
+func (t *USPDevice) Create() (WGConfigurer, error) {
 	log.Info("create tun interface")
 	tunIface, err := tun.CreateTUN(t.name, int(t.mtu))
 	if err != nil {
@@ -75,7 +75,7 @@ func (t *TunDevice) Create() (WGConfigurer, error) {
 	return t.configurer, nil
 }
 
-func (t *TunDevice) Up() (*udpmux.UniversalUDPMuxDefault, error) {
+func (t *USPDevice) Up() (*udpmux.UniversalUDPMuxDefault, error) {
 	if t.device == nil {
 		return nil, fmt.Errorf("device is not ready yet")
 	}
@@ -95,12 +95,12 @@ func (t *TunDevice) Up() (*udpmux.UniversalUDPMuxDefault, error) {
 	return udpMux, nil
 }
 
-func (t *TunDevice) UpdateAddr(address wgaddr.Address) error {
+func (t *USPDevice) UpdateAddr(address wgaddr.Address) error {
 	t.address = address
 	return t.assignAddr()
 }
 
-func (t *TunDevice) Close() error {
+func (t *USPDevice) Close() error {
 	if t.configurer != nil {
 		t.configurer.Close()
 	}
@@ -115,39 +115,39 @@ func (t *TunDevice) Close() error {
 	return nil
 }
 
-func (t *TunDevice) WgAddress() wgaddr.Address {
+func (t *USPDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
-func (t *TunDevice) MTU() uint16 {
+func (t *USPDevice) MTU() uint16 {
 	return t.mtu
 }
 
-func (t *TunDevice) DeviceName() string {
+func (t *USPDevice) DeviceName() string {
 	return t.name
 }
 
-func (t *TunDevice) FilteredDevice() *FilteredDevice {
+func (t *USPDevice) FilteredDevice() *FilteredDevice {
 	return t.filteredDevice
 }
 
 // Device returns the wireguard device
-func (t *TunDevice) Device() *device.Device {
+func (t *USPDevice) Device() *device.Device {
 	return t.device
 }
 
 // assignAddr Adds IP address to the tunnel interface
-func (t *TunDevice) assignAddr() error {
+func (t *USPDevice) assignAddr() error {
 	link := newWGLink(t.name)
 
-	return link.assignAddr(&t.address)
+	return link.assignAddr(t.address)
 }
 
-func (t *TunDevice) GetNet() *netstack.Net {
+func (t *USPDevice) GetNet() *netstack.Net {
 	return nil
 }
 
 // GetICEBind returns the ICEBind instance
-func (t *TunDevice) GetICEBind() EndpointManager {
+func (t *USPDevice) GetICEBind() EndpointManager {
 	return t.iceBind
 }

client/iface/device/device_windows.go

@@ -87,21 +87,7 @@ func (t *TunDevice) Create() (WGConfigurer, error) {
 	err = nbiface.Set()
 	if err != nil {
 		t.device.Close()
-		return nil, fmt.Errorf("set IPv4 interface MTU: %s", err)
-	}
-
-	if t.address.HasIPv6() {
-		nbiface6, err := luid.IPInterface(windows.AF_INET6)
-		if err != nil {
-			log.Warnf("failed to get IPv6 interface for MTU, continuing v4-only: %v", err)
-			t.address.ClearIPv6()
-		} else {
-			nbiface6.NLMTU = uint32(t.mtu)
-			if err := nbiface6.Set(); err != nil {
-				log.Warnf("failed to set IPv6 interface MTU, continuing v4-only: %v", err)
-				t.address.ClearIPv6()
-			}
-		}
+		return nil, fmt.Errorf("got error when getting setting the interface mtu: %s", err)
 	}
 	err = t.assignAddr()
 	if err != nil {
@@ -192,21 +178,8 @@ func (t *TunDevice) GetInterfaceGUIDString() (string, error) {
 // assignAddr Adds IP address to the tunnel interface and network route based on the range provided
 func (t *TunDevice) assignAddr() error {
 	luid := winipcfg.LUID(t.nativeTunDevice.LUID())
-
-	v4Prefix := t.address.Prefix()
-	if t.address.HasIPv6() {
-		v6Prefix := t.address.IPv6Prefix()
-		log.Debugf("adding addresses %s, %s to interface: %s", v4Prefix, v6Prefix, t.name)
-		if err := luid.SetIPAddresses([]netip.Prefix{v4Prefix, v6Prefix}); err != nil {
-			log.Warnf("failed to assign dual-stack addresses, retrying v4-only: %v", err)
-			t.address.ClearIPv6()
-			return luid.SetIPAddresses([]netip.Prefix{v4Prefix})
-		}
-		return nil
-	}
-
-	log.Debugf("adding address %s to interface: %s", v4Prefix, t.name)
-	return luid.SetIPAddresses([]netip.Prefix{v4Prefix})
+	log.Debugf("adding address %s to interface: %s", t.address.IP, t.name)
+	return luid.SetIPAddresses([]netip.Prefix{netip.MustParsePrefix(t.address.String())})
 }
 
 func (t *TunDevice) GetNet() *netstack.Net {

client/iface/device/kernel_module.go

@@ -0,0 +1,8 @@
+//go:build (!linux && !freebsd) || android
+
+package device
+
+// WireGuardModuleIsLoaded check if we can load WireGuard mod (linux only)
+func WireGuardModuleIsLoaded() bool {
+	return false
+}

client/iface/device/kernel_module_freebsd.go

@@ -0,0 +1,18 @@
+package device
+
+// WireGuardModuleIsLoaded check if kernel support wireguard
+func WireGuardModuleIsLoaded() bool {
+	// Despite the fact FreeBSD natively support Wireguard (https://github.com/WireGuard/wireguard-freebsd)
+	//  we are currently do not use it, since it is required to add wireguard kernel support to
+	//   - https://github.com/netbirdio/netbird/tree/main/sharedsock
+	//   - https://github.com/mdlayher/socket
+	// TODO: implement kernel space
+	return false
+}
+
+// ModuleTunIsLoaded check if tun module exist, if is not attempt to load it
+func ModuleTunIsLoaded() bool {
+	// Assume tun supported by freebsd kernel by default
+	// TODO: implement check for module loaded in kernel or build-it
+	return true
+}

client/iface/device/kernel_module_nonlinux.go

@@ -1,13 +0,0 @@
-//go:build !linux || android
-
-package device
-
-// WireGuardModuleIsLoaded reports whether the kernel WireGuard module is available.
-func WireGuardModuleIsLoaded() bool {
-	return false
-}
-
-// ModuleTunIsLoaded reports whether the tun device is available.
-func ModuleTunIsLoaded() bool {
-	return true
-}

client/iface/device/wg_link_freebsd.go

@@ -2,7 +2,6 @@ package device
 
 import (
 	"fmt"
-	"os/exec"
 
 	log "github.com/sirupsen/logrus"
 
@@ -58,32 +57,32 @@ func (l *wgLink) up() error {
 	return nil
 }
 
-func (l *wgLink) assignAddr(address *wgaddr.Address) error {
+func (l *wgLink) assignAddr(address wgaddr.Address) error {
 	link, err := freebsd.LinkByName(l.name)
 	if err != nil {
 		return fmt.Errorf("link by name: %w", err)
 	}
 
+	ip := address.IP.String()
+
+	// Convert prefix length to hex netmask
 	prefixLen := address.Network.Bits()
+	if !address.IP.Is4() {
+		return fmt.Errorf("IPv6 not supported for interface assignment")
+	}
+
 	maskBits := uint32(0xffffffff) << (32 - prefixLen)
 	mask := fmt.Sprintf("0x%08x", maskBits)
 
-	log.Infof("assign addr %s mask %s to %s interface", address.IP, mask, l.name)
+	log.Infof("assign addr %s mask %s to %s interface", ip, mask, l.name)
 
-	if err := link.AssignAddr(address.IP.String(), mask); err != nil {
+	err = link.AssignAddr(ip, mask)
+	if err != nil {
 		return fmt.Errorf("assign addr: %w", err)
 	}
 
-	if address.HasIPv6() {
-		log.Infof("assign IPv6 addr %s to %s interface", address.IPv6String(), l.name)
-		cmd := exec.Command("ifconfig", l.name, "inet6", address.IPv6String())
-		if out, err := cmd.CombinedOutput(); err != nil {
-			log.Warnf("failed to assign IPv6 address %s to %s, continuing v4-only: %s: %v", address.IPv6String(), l.name, string(out), err)
-			address.ClearIPv6()
-		}
-	}
-
-	if err := link.Up(); err != nil {
+	err = link.Up()
+	if err != nil {
 		return fmt.Errorf("up: %w", err)
 	}
 

client/iface/device/wg_link_linux.go

@@ -4,8 +4,6 @@ package device
 
 import (
 	"fmt"
-	"net"
-	"net/netip"
 	"os"
 
 	log "github.com/sirupsen/logrus"
@@ -94,7 +92,7 @@ func (l *wgLink) up() error {
 	return nil
 }
 
-func (l *wgLink) assignAddr(address *wgaddr.Address) error {
+func (l *wgLink) assignAddr(address wgaddr.Address) error {
 	//delete existing addresses
 	list, err := netlink.AddrList(l, 0)
 	if err != nil {
@@ -112,16 +110,20 @@ func (l *wgLink) assignAddr(address *wgaddr.Address) error {
 	}
 
 	name := l.attrs.Name
+	addrStr := address.String()
 
-	if err := l.addAddr(name, address.Prefix()); err != nil {
-		return err
+	log.Debugf("adding address %s to interface: %s", addrStr, name)
+
+	addr, err := netlink.ParseAddr(addrStr)
+	if err != nil {
+		return fmt.Errorf("parse addr: %w", err)
 	}
 
-	if address.HasIPv6() {
-		if err := l.addAddr(name, address.IPv6Prefix()); err != nil {
-			log.Warnf("failed to assign IPv6 address %s to %s, continuing v4-only: %v", address.IPv6Prefix(), name, err)
-			address.ClearIPv6()
-		}
+	err = netlink.AddrAdd(l, addr)
+	if os.IsExist(err) {
+		log.Infof("interface %s already has the address: %s", name, addrStr)
+	} else if err != nil {
+		return fmt.Errorf("add addr: %w", err)
 	}
 
 	// On linux, the link must be brought up
@@ -131,22 +133,3 @@ func (l *wgLink) assignAddr(address *wgaddr.Address) error {
 
 	return nil
 }
-
-func (l *wgLink) addAddr(ifaceName string, prefix netip.Prefix) error {
-	log.Debugf("adding address %s to interface: %s", prefix, ifaceName)
-
-	addr := &netlink.Addr{
-		IPNet: &net.IPNet{
-			IP:   prefix.Addr().AsSlice(),
-			Mask: net.CIDRMask(prefix.Bits(), prefix.Addr().BitLen()),
-		},
-	}
-
-	if err := netlink.AddrAdd(l, addr); os.IsExist(err) {
-		log.Infof("interface %s already has the address: %s", ifaceName, prefix)
-	} else if err != nil {
-		return fmt.Errorf("add addr %s: %w", prefix, err)
-	}
-
-	return nil
-}

client/iface/iface.go

@@ -57,7 +57,7 @@ type wgProxyFactory interface {
 
 type WGIFaceOpts struct {
 	IFaceName    string
-	Address      wgaddr.Address
+	Address      string
 	WGPort       int
 	WGPrivKey    string
 	MTU          uint16
@@ -141,11 +141,16 @@ func (w *WGIface) Up() (*udpmux.UniversalUDPMuxDefault, error) {
 }
 
 // UpdateAddr updates address of the interface
-func (w *WGIface) UpdateAddr(newAddr wgaddr.Address) error {
+func (w *WGIface) UpdateAddr(newAddr string) error {
 	w.mu.Lock()
 	defer w.mu.Unlock()
 
-	return w.tun.UpdateAddr(newAddr)
+	addr, err := wgaddr.ParseWGAddress(newAddr)
+	if err != nil {
+		return err
+	}
+
+	return w.tun.UpdateAddr(addr)
 }
 
 // UpdatePeer updates existing Wireguard Peer or creates a new one if doesn't exist

client/iface/iface_new_android.go

@@ -4,17 +4,23 @@ import (
 	"github.com/netbirdio/netbird/client/iface/bind"
 	"github.com/netbirdio/netbird/client/iface/device"
 	"github.com/netbirdio/netbird/client/iface/netstack"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/iface/wgproxy"
 )
 
 // NewWGIFace Creates a new WireGuard interface instance
 func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, opts.Address, opts.MTU)
+	wgAddress, err := wgaddr.ParseWGAddress(opts.Address)
+	if err != nil {
+		return nil, err
+	}
+
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 
 	if netstack.IsEnabled() {
 		wgIFace := &WGIface{
 			userspaceBind:  true,
-			tun:            device.NewNetstackDevice(opts.IFaceName, opts.Address, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr()),
+			tun:            device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr()),
 			wgProxyFactory: wgproxy.NewUSPFactory(iceBind, opts.MTU),
 		}
 		return wgIFace, nil
@@ -22,7 +28,7 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 
 	wgIFace := &WGIface{
 		userspaceBind:  true,
-		tun:            device.NewTunDevice(opts.Address, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, opts.MobileArgs.TunAdapter, opts.DisableDNS),
+		tun:            device.NewTunDevice(wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, opts.MobileArgs.TunAdapter, opts.DisableDNS),
 		wgProxyFactory: wgproxy.NewUSPFactory(iceBind, opts.MTU),
 	}
 	return wgIFace, nil

client/iface/iface_new_darwin.go

@@ -0,0 +1,35 @@
+//go:build !ios
+
+package iface
+
+import (
+	"github.com/netbirdio/netbird/client/iface/bind"
+	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/netstack"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+	"github.com/netbirdio/netbird/client/iface/wgproxy"
+)
+
+// NewWGIFace Creates a new WireGuard interface instance
+func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
+	wgAddress, err := wgaddr.ParseWGAddress(opts.Address)
+	if err != nil {
+		return nil, err
+	}
+
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
+
+	var tun WGTunDevice
+	if netstack.IsEnabled() {
+		tun = device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr())
+	} else {
+		tun = device.NewTunDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind)
+	}
+
+	wgIFace := &WGIface{
+		userspaceBind:  true,
+		tun:            tun,
+		wgProxyFactory: wgproxy.NewUSPFactory(iceBind, opts.MTU),
+	}
+	return wgIFace, nil
+}

client/iface/iface_new_freebsd.go

@@ -0,0 +1,41 @@
+//go:build freebsd
+
+package iface
+
+import (
+	"fmt"
+
+	"github.com/netbirdio/netbird/client/iface/bind"
+	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/netstack"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+	"github.com/netbirdio/netbird/client/iface/wgproxy"
+)
+
+// NewWGIFace Creates a new WireGuard interface instance
+func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
+	wgAddress, err := wgaddr.ParseWGAddress(opts.Address)
+	if err != nil {
+		return nil, err
+	}
+
+	wgIFace := &WGIface{}
+
+	if netstack.IsEnabled() {
+		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
+		wgIFace.tun = device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr())
+		wgIFace.userspaceBind = true
+		wgIFace.wgProxyFactory = wgproxy.NewUSPFactory(iceBind, opts.MTU)
+		return wgIFace, nil
+	}
+
+	if device.ModuleTunIsLoaded() {
+		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
+		wgIFace.tun = device.NewUSPDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind)
+		wgIFace.userspaceBind = true
+		wgIFace.wgProxyFactory = wgproxy.NewUSPFactory(iceBind, opts.MTU)
+		return wgIFace, nil
+	}
+
+	return nil, fmt.Errorf("couldn't check or load tun module")
+}

client/iface/iface_new_ios.go

@@ -5,15 +5,21 @@ package iface
 import (
 	"github.com/netbirdio/netbird/client/iface/bind"
 	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/iface/wgproxy"
 )
 
 // NewWGIFace Creates a new WireGuard interface instance
 func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, opts.Address, opts.MTU)
+	wgAddress, err := wgaddr.ParseWGAddress(opts.Address)
+	if err != nil {
+		return nil, err
+	}
+
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 
 	wgIFace := &WGIface{
-		tun:            device.NewTunDevice(opts.IFaceName, opts.Address, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, opts.MobileArgs.TunFd),
+		tun:            device.NewTunDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, opts.MobileArgs.TunFd),
 		userspaceBind:  true,
 		wgProxyFactory: wgproxy.NewUSPFactory(iceBind, opts.MTU),
 	}

client/iface/iface_new_js.go

@@ -4,15 +4,21 @@ import (
 	"github.com/netbirdio/netbird/client/iface/bind"
 	"github.com/netbirdio/netbird/client/iface/device"
 	"github.com/netbirdio/netbird/client/iface/netstack"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/iface/wgproxy"
 )
 
 // NewWGIFace creates a new WireGuard interface for WASM (always uses netstack mode)
 func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
+	wgAddress, err := wgaddr.ParseWGAddress(opts.Address)
+	if err != nil {
+		return nil, err
+	}
+
 	relayBind := bind.NewRelayBindJS()
 
 	wgIface := &WGIface{
-		tun:            device.NewNetstackDevice(opts.IFaceName, opts.Address, opts.WGPort, opts.WGPrivKey, opts.MTU, relayBind, netstack.ListenAddr()),
+		tun:            device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, relayBind, netstack.ListenAddr()),
 		userspaceBind:  true,
 		wgProxyFactory: wgproxy.NewUSPFactory(relayBind, opts.MTU),
 	}

client/iface/iface_new_linux.go

@@ -3,40 +3,44 @@
 package iface
 
 import (
-	"errors"
+	"fmt"
 
 	"github.com/netbirdio/netbird/client/iface/bind"
 	"github.com/netbirdio/netbird/client/iface/device"
 	"github.com/netbirdio/netbird/client/iface/netstack"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/iface/wgproxy"
 )
 
 // NewWGIFace Creates a new WireGuard interface instance
 func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
+	wgAddress, err := wgaddr.ParseWGAddress(opts.Address)
+	if err != nil {
+		return nil, err
+	}
+
+	wgIFace := &WGIface{}
+
 	if netstack.IsEnabled() {
-		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, opts.Address, opts.MTU)
-		return &WGIface{
-			tun:            device.NewNetstackDevice(opts.IFaceName, opts.Address, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr()),
-			userspaceBind:  true,
-			wgProxyFactory: wgproxy.NewUSPFactory(iceBind, opts.MTU),
-		}, nil
+		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
+		wgIFace.tun = device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr())
+		wgIFace.userspaceBind = true
+		wgIFace.wgProxyFactory = wgproxy.NewUSPFactory(iceBind, opts.MTU)
+		return wgIFace, nil
 	}
 
 	if device.WireGuardModuleIsLoaded() {
-		return &WGIface{
-			tun:            device.NewKernelDevice(opts.IFaceName, opts.Address, opts.WGPort, opts.WGPrivKey, opts.MTU, opts.TransportNet),
-			wgProxyFactory: wgproxy.NewKernelFactory(opts.WGPort, opts.MTU),
-		}, nil
+		wgIFace.tun = device.NewKernelDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, opts.TransportNet)
+		wgIFace.wgProxyFactory = wgproxy.NewKernelFactory(opts.WGPort, opts.MTU)
+		return wgIFace, nil
 	}
-
 	if device.ModuleTunIsLoaded() {
-		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, opts.Address, opts.MTU)
-		return &WGIface{
-			tun:            device.NewTunDevice(opts.IFaceName, opts.Address, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind),
-			userspaceBind:  true,
-			wgProxyFactory: wgproxy.NewUSPFactory(iceBind, opts.MTU),
-		}, nil
+		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
+		wgIFace.tun = device.NewUSPDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind)
+		wgIFace.userspaceBind = true
+		wgIFace.wgProxyFactory = wgproxy.NewUSPFactory(iceBind, opts.MTU)
+		return wgIFace, nil
 	}
 
-	return nil, errors.New("tun module not available")
+	return nil, fmt.Errorf("couldn't check or load tun module")
 }

client/iface/iface_new_windows.go

@@ -1,28 +1,33 @@
-//go:build !linux && !ios && !android && !js
-
 package iface
 
 import (
 	"github.com/netbirdio/netbird/client/iface/bind"
 	"github.com/netbirdio/netbird/client/iface/device"
 	"github.com/netbirdio/netbird/client/iface/netstack"
+	wgaddr "github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/iface/wgproxy"
 )
 
 // NewWGIFace Creates a new WireGuard interface instance
 func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, opts.Address, opts.MTU)
+	wgAddress, err := wgaddr.ParseWGAddress(opts.Address)
+	if err != nil {
+		return nil, err
+	}
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 
 	var tun WGTunDevice
 	if netstack.IsEnabled() {
-		tun = device.NewNetstackDevice(opts.IFaceName, opts.Address, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr())
+		tun = device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr())
 	} else {
-		tun = device.NewTunDevice(opts.IFaceName, opts.Address, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind)
+		tun = device.NewTunDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind)
 	}
 
-	return &WGIface{
+	wgIFace := &WGIface{
 		userspaceBind:  true,
 		tun:            tun,
 		wgProxyFactory: wgproxy.NewUSPFactory(iceBind, opts.MTU),
-	}, nil
+	}
+	return wgIFace, nil
+
 }

client/iface/iface_test.go

@@ -16,7 +16,6 @@ import (
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 
 	"github.com/netbirdio/netbird/client/iface/device"
-	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
 )
 
@@ -49,7 +48,7 @@ func TestWGIface_UpdateAddr(t *testing.T) {
 
 	opts := WGIFaceOpts{
 		IFaceName:    ifaceName,
-		Address:      wgaddr.MustParseWGAddress(addr),
+		Address:      addr,
 		WGPort:       wgPort,
 		WGPrivKey:    key,
 		MTU:          DefaultMTU,
@@ -85,7 +84,7 @@ func TestWGIface_UpdateAddr(t *testing.T) {
 
 	//update WireGuard address
 	addr = "100.64.0.2/8"
-	err = iface.UpdateAddr(wgaddr.MustParseWGAddress(addr))
+	err = iface.UpdateAddr(addr)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -131,7 +130,7 @@ func Test_CreateInterface(t *testing.T) {
 	}
 	opts := WGIFaceOpts{
 		IFaceName:    ifaceName,
-		Address:      wgaddr.MustParseWGAddress(wgIP),
+		Address:      wgIP,
 		WGPort:       33100,
 		WGPrivKey:    key,
 		MTU:          DefaultMTU,
@@ -175,7 +174,7 @@ func Test_Close(t *testing.T) {
 
 	opts := WGIFaceOpts{
 		IFaceName:    ifaceName,
-		Address:      wgaddr.MustParseWGAddress(wgIP),
+		Address:      wgIP,
 		WGPort:       wgPort,
 		WGPrivKey:    key,
 		MTU:          DefaultMTU,
@@ -220,7 +219,7 @@ func TestRecreation(t *testing.T) {
 
 			opts := WGIFaceOpts{
 				IFaceName:    ifaceName,
-				Address:      wgaddr.MustParseWGAddress(wgIP),
+				Address:      wgIP,
 				WGPort:       wgPort,
 				WGPrivKey:    key,
 				MTU:          DefaultMTU,
@@ -292,7 +291,7 @@ func Test_ConfigureInterface(t *testing.T) {
 	}
 	opts := WGIFaceOpts{
 		IFaceName:    ifaceName,
-		Address:      wgaddr.MustParseWGAddress(wgIP),
+		Address:      wgIP,
 		WGPort:       wgPort,
 		WGPrivKey:    key,
 		MTU:          DefaultMTU,
@@ -348,7 +347,7 @@ func Test_UpdatePeer(t *testing.T) {
 
 	opts := WGIFaceOpts{
 		IFaceName:    ifaceName,
-		Address:      wgaddr.MustParseWGAddress(wgIP),
+		Address:      wgIP,
 		WGPort:       33100,
 		WGPrivKey:    key,
 		MTU:          DefaultMTU,
@@ -418,7 +417,7 @@ func Test_RemovePeer(t *testing.T) {
 
 	opts := WGIFaceOpts{
 		IFaceName:    ifaceName,
-		Address:      wgaddr.MustParseWGAddress(wgIP),
+		Address:      wgIP,
 		WGPort:       33100,
 		WGPrivKey:    key,
 		MTU:          DefaultMTU,
@@ -483,7 +482,7 @@ func Test_ConnectPeers(t *testing.T) {
 
 	optsPeer1 := WGIFaceOpts{
 		IFaceName:    peer1ifaceName,
-		Address:      wgaddr.MustParseWGAddress(peer1wgIP.String()),
+		Address:      peer1wgIP.String(),
 		WGPort:       peer1wgPort,
 		WGPrivKey:    peer1Key.String(),
 		MTU:          DefaultMTU,
@@ -523,7 +522,7 @@ func Test_ConnectPeers(t *testing.T) {
 
 	optsPeer2 := WGIFaceOpts{
 		IFaceName:    peer2ifaceName,
-		Address:      wgaddr.MustParseWGAddress(peer2wgIP.String()),
+		Address:      peer2wgIP.String(),
 		WGPort:       peer2wgPort,
 		WGPrivKey:    peer2Key.String(),
 		MTU:          DefaultMTU,

client/iface/netstack/tun.go

@@ -13,7 +13,7 @@ import (
 const EnvSkipProxy = "NB_NETSTACK_SKIP_PROXY"
 
 type NetStackTun struct { //nolint:revive
-	addresses     []netip.Addr
+	address       netip.Addr
 	dnsAddress    netip.Addr
 	mtu           int
 	listenAddress string
@@ -22,9 +22,9 @@ type NetStackTun struct { //nolint:revive
 	tundev tun.Device
 }
 
-func NewNetStackTun(listenAddress string, addresses []netip.Addr, dnsAddress netip.Addr, mtu int) *NetStackTun {
+func NewNetStackTun(listenAddress string, address netip.Addr, dnsAddress netip.Addr, mtu int) *NetStackTun {
 	return &NetStackTun{
-		addresses:     addresses,
+		address:       address,
 		dnsAddress:    dnsAddress,
 		mtu:           mtu,
 		listenAddress: listenAddress,
@@ -33,7 +33,7 @@ func NewNetStackTun(listenAddress string, addresses []netip.Addr, dnsAddress net
 
 func (t *NetStackTun) Create() (tun.Device, *netstack.Net, error) {
 	nsTunDev, tunNet, err := netstack.CreateNetTUN(
-		t.addresses,
+		[]netip.Addr{t.address},
 		[]netip.Addr{t.dnsAddress},
 		t.mtu)
 	if err != nil {

client/iface/wgaddr/address.go

@@ -3,18 +3,12 @@ package wgaddr
 import (
 	"fmt"
 	"net/netip"
-
-	"github.com/netbirdio/netbird/shared/netiputil"
 )
 
 // Address WireGuard parsed address
 type Address struct {
 	IP      netip.Addr
 	Network netip.Prefix
-
-	// IPv6 overlay address, if assigned.
-	IPv6    netip.Addr
-	IPv6Net netip.Prefix
 }
 
 // ParseWGAddress parse a string ("1.2.3.4/24") address to WG Address
@@ -29,60 +23,6 @@ func ParseWGAddress(address string) (Address, error) {
 	}, nil
 }
 
-// HasIPv6 reports whether a v6 overlay address is assigned.
-func (addr Address) HasIPv6() bool {
-	return addr.IPv6.IsValid()
-}
-
 func (addr Address) String() string {
-	return addr.Prefix().String()
-}
-
-// IPv6String returns the v6 address in CIDR notation, or empty string if none.
-func (addr Address) IPv6String() string {
-	if !addr.HasIPv6() {
-		return ""
-	}
-	return addr.IPv6Prefix().String()
-}
-
-// Prefix returns the v4 host address with its network prefix length (e.g. 100.64.0.1/16).
-func (addr Address) Prefix() netip.Prefix {
-	return netip.PrefixFrom(addr.IP, addr.Network.Bits())
-}
-
-// IPv6Prefix returns the v6 host address with its network prefix length, or a zero prefix if none.
-func (addr Address) IPv6Prefix() netip.Prefix {
-	if !addr.HasIPv6() {
-		return netip.Prefix{}
-	}
-	return netip.PrefixFrom(addr.IPv6, addr.IPv6Net.Bits())
-}
-
-// SetIPv6FromCompact decodes a compact prefix (5 or 17 bytes) and sets the IPv6 fields.
-// Returns an error if the bytes are invalid. A nil or empty input is a no-op.
-//
-//nolint:recvcheck
-func (addr *Address) SetIPv6FromCompact(raw []byte) error {
-	if len(raw) == 0 {
-		return nil
-	}
-	prefix, err := netiputil.DecodePrefix(raw)
-	if err != nil {
-		return fmt.Errorf("decode v6 overlay address: %w", err)
-	}
-	if !prefix.Addr().Is6() {
-		return fmt.Errorf("expected IPv6 address, got %s", prefix.Addr())
-	}
-	addr.IPv6 = prefix.Addr()
-	addr.IPv6Net = prefix.Masked()
-	return nil
-}
-
-// ClearIPv6 removes the IPv6 overlay address, leaving only v4.
-//
-//nolint:recvcheck
-func (addr *Address) ClearIPv6() {
-	addr.IPv6 = netip.Addr{}
-	addr.IPv6Net = netip.Prefix{}
+	return fmt.Sprintf("%s/%d", addr.IP.String(), addr.Network.Bits())
 }

client/iface/wgaddr/address_test_helpers.go

@@ -1,10 +0,0 @@
-package wgaddr
-
-// MustParseWGAddress parses and returns a WG Address, panicking on error.
-func MustParseWGAddress(address string) Address {
-	a, err := ParseWGAddress(address)
-	if err != nil {
-		panic(err)
-	}
-	return a
-}

client/iface/wgproxy/bind/proxy.go

@@ -6,7 +6,7 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
-
+	"strings"
 	"sync"
 
 	log "github.com/sirupsen/logrus"
@@ -196,25 +196,18 @@ func (p *ProxyBind) proxyToLocal(ctx context.Context) {
 	}
 }
 
-// fakeAddress returns a fake address that is used as an identifier for the peer.
-// The fake address is in the format of 127.1.x.x where x.x is derived from the
-// last two bytes of the peer address (works for both IPv4 and IPv6).
+// fakeAddress returns a fake address that is used to as an identifier for the peer.
+// The fake address is in the format of 127.1.x.x where x.x is the last two octets of the peer address.
 func fakeAddress(peerAddress *net.UDPAddr) (*netip.AddrPort, error) {
-	if peerAddress == nil {
-		return nil, fmt.Errorf("nil peer address")
-	}
-	if peerAddress.Port < 0 || peerAddress.Port > 65535 {
-		return nil, fmt.Errorf("invalid UDP port: %d", peerAddress.Port)
-	}
-
-	addr, ok := netip.AddrFromSlice(peerAddress.IP)
-	if !ok {
+	octets := strings.Split(peerAddress.IP.String(), ".")
+	if len(octets) != 4 {
 		return nil, fmt.Errorf("invalid IP format")
 	}
-	addr = addr.Unmap()
 
-	raw := addr.As16()
-	fakeIP := netip.AddrFrom4([4]byte{127, 1, raw[14], raw[15]})
+	fakeIP, err := netip.ParseAddr(fmt.Sprintf("127.1.%s.%s", octets[2], octets[3]))
+	if err != nil {
+		return nil, fmt.Errorf("parse new IP: %w", err)
+	}
 
 	netipAddr := netip.AddrPortFrom(fakeIP, uint16(peerAddress.Port))
 	return &netipAddr, nil

client/installer.nsis

@@ -280,6 +280,43 @@ CreateShortCut "$SMPROGRAMS\${APP_NAME}.lnk" "$INSTDIR\${UI_APP_EXE}"
 CreateShortCut "$DESKTOP\${APP_NAME}.lnk" "$INSTDIR\${UI_APP_EXE}"
 SectionEnd
 
+# Install the Microsoft Edge WebView2 runtime if it isn't already present.
+# Macro adapted from Wails3's NSIS template (wails_tools.nsh): a registry
+# probe followed by a silent install of the embedded evergreen bootstrapper.
+# The MicrosoftEdgeWebview2Setup.exe payload is staged next to this script
+# by the sign-pipelines build step (`wails3 generate webview2bootstrapper`).
+!macro nb.webview2runtime
+    SetRegView 64
+    # Per-machine install marker — populated when the runtime ships with
+    # Edge or has been installed by an admin previously.
+    ReadRegStr $0 HKLM "SOFTWARE\WOW6432Node\Microsoft\EdgeUpdate\Clients\{F3017226-FE2A-4295-8BDF-00C3A9A7E4C5}" "pv"
+    ${If} $0 != ""
+        Goto webview2_ok
+    ${EndIf}
+    # Per-user fallback for HKCU installs.
+    ReadRegStr $0 HKCU "Software\Microsoft\EdgeUpdate\Clients\{F3017226-FE2A-4295-8BDF-00C3A9A7E4C5}" "pv"
+    ${If} $0 != ""
+        Goto webview2_ok
+    ${EndIf}
+
+    SetDetailsPrint both
+    DetailPrint "Installing: WebView2 Runtime"
+    SetDetailsPrint listonly
+
+    InitPluginsDir
+    CreateDirectory "$pluginsdir\webview2bootstrapper"
+    SetOutPath "$pluginsdir\webview2bootstrapper"
+    File "MicrosoftEdgeWebview2Setup.exe"
+    ExecWait '"$pluginsdir\webview2bootstrapper\MicrosoftEdgeWebview2Setup.exe" /silent /install'
+
+    SetDetailsPrint both
+    webview2_ok:
+!macroend
+
+Section -WebView2
+    !insertmacro nb.webview2runtime
+SectionEnd
+
 Section -Post
 ExecWait '"$INSTDIR\${MAIN_APP_EXE}" service install'
 ExecWait '"$INSTDIR\${MAIN_APP_EXE}" service start'
@@ -326,9 +363,9 @@ DetailPrint "Deleting application files..."
 Delete "$INSTDIR\${UI_APP_EXE}"
 Delete "$INSTDIR\${MAIN_APP_EXE}"
 Delete "$INSTDIR\wintun.dll"
-!if ${ARCH} == "amd64"
+# Legacy: pre-Wails installs shipped opengl32.dll (Mesa3D for Fyne); remove
+# any leftover copy on uninstall so old upgrades don't leave it behind.
 Delete "$INSTDIR\opengl32.dll"
-!endif
 DetailPrint "Removing application directory..."
 RmDir /r "$INSTDIR"
 

client/internal/acl/manager.go

@@ -5,6 +5,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"net"
 	"net/netip"
 	"strconv"
 	"sync"
@@ -18,7 +19,6 @@ import (
 	"github.com/netbirdio/netbird/client/internal/acl/id"
 	"github.com/netbirdio/netbird/shared/management/domain"
 	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
-	"github.com/netbirdio/netbird/shared/netiputil"
 )
 
 var ErrSourceRangesEmpty = errors.New("sources range is empty")
@@ -105,10 +105,6 @@ func (d *DefaultManager) applyPeerACLs(networkMap *mgmProto.NetworkMap) {
 	newRulePairs := make(map[id.RuleID][]firewall.Rule)
 	ipsetByRuleSelectors := make(map[string]string)
 
-	// TODO: deny rules should be fatal: if a deny rule fails to apply, we must
-	// roll back all allow rules to avoid a fail-open where allowed traffic bypasses
-	// the missing deny. Currently we accumulate errors and continue.
-	var merr *multierror.Error
 	for _, r := range rules {
 		// if this rule is member of rule selection with more than DefaultIPsCountForSet
 		// it's IP address can be used in the ipset for firewall manager which supports it
@@ -121,8 +117,9 @@ func (d *DefaultManager) applyPeerACLs(networkMap *mgmProto.NetworkMap) {
 		}
 		pairID, rulePair, err := d.protoRuleToFirewallRule(r, ipsetName)
 		if err != nil {
-			merr = multierror.Append(merr, fmt.Errorf("apply firewall rule: %w", err))
-			continue
+			log.Errorf("failed to apply firewall rule: %+v, %v", r, err)
+			d.rollBack(newRulePairs)
+			break
 		}
 		if len(rulePair) > 0 {
 			d.peerRulesPairs[pairID] = rulePair
@@ -130,10 +127,6 @@ func (d *DefaultManager) applyPeerACLs(networkMap *mgmProto.NetworkMap) {
 		}
 	}
 
-	if merr != nil {
-		log.Errorf("failed to apply %d peer ACL rule(s): %v", merr.Len(), nberrors.FormatErrorOrNil(merr))
-	}
-
 	for pairID, rules := range d.peerRulesPairs {
 		if _, ok := newRulePairs[pairID]; !ok {
 			for _, rule := range rules {
@@ -223,9 +216,9 @@ func (d *DefaultManager) protoRuleToFirewallRule(
 	r *mgmProto.FirewallRule,
 	ipsetName string,
 ) (id.RuleID, []firewall.Rule, error) {
-	ip, err := extractRuleIP(r)
-	if err != nil {
-		return "", nil, err
+	ip := net.ParseIP(r.PeerIP)
+	if ip == nil {
+		return "", nil, fmt.Errorf("invalid IP address, skipping firewall rule")
 	}
 
 	protocol, err := convertToFirewallProtocol(r.Protocol)
@@ -296,13 +289,13 @@ func portInfoEmpty(portInfo *mgmProto.PortInfo) bool {
 
 func (d *DefaultManager) addInRules(
 	id []byte,
-	ip netip.Addr,
+	ip net.IP,
 	protocol firewall.Protocol,
 	port *firewall.Port,
 	action firewall.Action,
 	ipsetName string,
 ) ([]firewall.Rule, error) {
-	rule, err := d.firewall.AddPeerFiltering(id, ip.AsSlice(), protocol, nil, port, action, ipsetName)
+	rule, err := d.firewall.AddPeerFiltering(id, ip, protocol, nil, port, action, ipsetName)
 	if err != nil {
 		return nil, fmt.Errorf("add firewall rule: %w", err)
 	}
@@ -312,7 +305,7 @@ func (d *DefaultManager) addInRules(
 
 func (d *DefaultManager) addOutRules(
 	id []byte,
-	ip netip.Addr,
+	ip net.IP,
 	protocol firewall.Protocol,
 	port *firewall.Port,
 	action firewall.Action,
@@ -322,7 +315,7 @@ func (d *DefaultManager) addOutRules(
 		return nil, nil
 	}
 
-	rule, err := d.firewall.AddPeerFiltering(id, ip.AsSlice(), protocol, port, nil, action, ipsetName)
+	rule, err := d.firewall.AddPeerFiltering(id, ip, protocol, port, nil, action, ipsetName)
 	if err != nil {
 		return nil, fmt.Errorf("add firewall rule: %w", err)
 	}
@@ -330,9 +323,9 @@ func (d *DefaultManager) addOutRules(
 	return rule, nil
 }
 
-// getPeerRuleID returns unique ID for the rule based on its parameters.
+// getPeerRuleID() returns unique ID for the rule based on its parameters.
 func (d *DefaultManager) getPeerRuleID(
-	ip netip.Addr,
+	ip net.IP,
 	proto firewall.Protocol,
 	direction int,
 	port *firewall.Port,
@@ -351,25 +344,15 @@ func (d *DefaultManager) getRuleGroupingSelector(rule *mgmProto.FirewallRule) st
 	return fmt.Sprintf("%v:%v:%v:%s:%v", strconv.Itoa(int(rule.Direction)), rule.Action, rule.Protocol, rule.Port, rule.PortInfo)
 }
 
-
-// extractRuleIP extracts the peer IP from a firewall rule.
-// If sourcePrefixes is populated (new management), decode the first entry and use its address.
-// Otherwise fall back to the deprecated PeerIP string field (old management).
-func extractRuleIP(r *mgmProto.FirewallRule) (netip.Addr, error) {
-	if len(r.SourcePrefixes) > 0 {
-		addr, err := netiputil.DecodeAddr(r.SourcePrefixes[0])
-		if err != nil {
-			return netip.Addr{}, fmt.Errorf("decode source prefix: %w", err)
+func (d *DefaultManager) rollBack(newRulePairs map[id.RuleID][]firewall.Rule) {
+	log.Debugf("rollback ACL to previous state")
+	for _, rules := range newRulePairs {
+		for _, rule := range rules {
+			if err := d.firewall.DeletePeerRule(rule); err != nil {
+				log.Errorf("failed to delete new firewall rule (id: %v) during rollback: %v", rule.ID(), err)
+			}
 		}
-		return addr.Unmap(), nil
 	}
-
-	//nolint:staticcheck // PeerIP used for backward compatibility with old management
-	addr, err := netip.ParseAddr(r.PeerIP)
-	if err != nil {
-		return netip.Addr{}, fmt.Errorf("invalid IP address, skipping firewall rule")
-	}
-	return addr.Unmap(), nil
 }
 
 func convertToFirewallProtocol(protocol mgmProto.RuleProtocol) (firewall.Protocol, error) {

client/internal/auth/auth.go

@@ -321,7 +321,6 @@ func (a *Auth) setSystemInfoFlags(info *system.Info) {
 		a.config.DisableFirewall,
 		a.config.BlockLANAccess,
 		a.config.BlockInbound,
-		a.config.DisableIPv6,
 		a.config.LazyConnectionEnabled,
 		a.config.EnableSSHRoot,
 		a.config.EnableSSHSFTP,

client/internal/connect.go

@@ -14,13 +14,10 @@ import (
 
 	"github.com/cenkalti/backoff/v4"
 	log "github.com/sirupsen/logrus"
-
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 	"google.golang.org/grpc/codes"
 	gstatus "google.golang.org/grpc/status"
 
-	"github.com/netbirdio/netbird/client/iface/wgaddr"
-
 	"github.com/netbirdio/netbird/client/iface"
 	"github.com/netbirdio/netbird/client/iface/device"
 	"github.com/netbirdio/netbird/client/iface/netstack"
@@ -539,20 +536,9 @@ func createEngineConfig(key wgtypes.Key, config *profilemanager.Config, peerConf
 	if config.NetworkMonitor != nil {
 		nm = *config.NetworkMonitor
 	}
-	wgAddr, err := wgaddr.ParseWGAddress(peerConfig.Address)
-	if err != nil {
-		return nil, fmt.Errorf("parse overlay address %q: %w", peerConfig.Address, err)
-	}
-
-	if !config.DisableIPv6 {
-		if err := wgAddr.SetIPv6FromCompact(peerConfig.GetAddressV6()); err != nil {
-			log.Warn(err)
-		}
-	}
-
 	engineConf := &EngineConfig{
 		WgIfaceName:                   config.WgIface,
-		WgAddr:                        wgAddr,
+		WgAddr:                        peerConfig.Address,
 		IFaceBlackList:                config.IFaceBlackList,
 		DisableIPv6Discovery:          config.DisableIPv6Discovery,
 		WgPrivateKey:                  key,
@@ -577,7 +563,6 @@ func createEngineConfig(key wgtypes.Key, config *profilemanager.Config, peerConf
 		DisableFirewall:     config.DisableFirewall,
 		BlockLANAccess:      config.BlockLANAccess,
 		BlockInbound:        config.BlockInbound,
-		DisableIPv6:         config.DisableIPv6,
 
 		LazyConnectionEnabled: config.LazyConnectionEnabled,
 
@@ -652,7 +637,6 @@ func loginToManagement(ctx context.Context, client mgm.Client, pubSSHKey []byte,
 		config.DisableFirewall,
 		config.BlockLANAccess,
 		config.BlockInbound,
-		config.DisableIPv6,
 		config.LazyConnectionEnabled,
 		config.EnableSSHRoot,
 		config.EnableSSHSFTP,

client/internal/connect_android_default.go

@@ -40,10 +40,6 @@ func (noopNetworkChangeListener) SetInterfaceIP(string) {
 	// network stack, not by OS-level interface configuration.
 }
 
-func (noopNetworkChangeListener) SetInterfaceIPv6(string) {
-	// No-op: same as SetInterfaceIP, IPv6 overlay is managed by userspace stack.
-}
-
 // noopDnsReadyListener is a stub for embed.Client on Android.
 // DNS readiness notifications are not needed in netstack/embed mode
 // since system DNS is disabled and DNS resolution happens externally.