[GH-ISSUE #5496] Netbird Client seems to clash with Pangolin #10636

New Issue

saavagebueno · 2026-08-05T01:26:42-04:00

saavagebueno commented

2026-08-05 01:26:42 -04:00

Originally created by @Dimtar on GitHub (Mar 4, 2026).
Original GitHub issue: https://github.com/netbirdio/netbird/issues/5496

Hi all.

My Pangolin instance has stopped and I was getting an error when trying to start the container stack/compose stack.

Error response from daemon: failed to set up container networking: driver failed programming external connectivity on endpoint gerbil (28a33346188dd1abd4946cc52b25bd9fb4883d1ceb8612670dc95487be120c6c): failed to bind host port 0.0.0.0:51820/udp: address already in use

I ran a few commands and after a few reboots and with all containers stopped something was taking port UDP/51820. The OS wasn't reporting what that was:

sudo ss -tulnp | grep 51820
udp UNCONN 0 0 0.0.0.0:51820 0.0.0.0:*
udp UNCONN 0 0 [::]:51820 [::]:*

I posted on the Pangolin Discord and a very helpful member suggested they had the same issue and it was likely Netbird. If I run netbird down then I can start the pangolin stack without issues.

I'm not sure if this is something that is fixable but it seems Netbird (the client) is taking UDP/51820 and this can clearly conflict. Happy to provide any additional information needed.

Originally created by @Dimtar on GitHub (Mar 4, 2026). Original GitHub issue: https://github.com/netbirdio/netbird/issues/5496 Hi all. My Pangolin instance has stopped and I was getting an error when trying to start the container stack/compose stack. `Error response from daemon: failed to set up container networking: driver failed programming external connectivity on endpoint gerbil (28a33346188dd1abd4946cc52b25bd9fb4883d1ceb8612670dc95487be120c6c): failed to bind host port 0.0.0.0:51820/udp: address already in use` I ran a few commands and after a few reboots and with all containers stopped something was taking port UDP/51820. The OS wasn't reporting what that was: `sudo ss -tulnp | grep 51820` `udp UNCONN 0 0 0.0.0.0:51820 0.0.0.0:*` `udp UNCONN 0 0 [::]:51820 [::]:* ` I posted on the Pangolin Discord and a very helpful member suggested they had the same issue and it was likely Netbird. If I run `netbird down` then I can start the pangolin stack without issues. I'm not sure if this is something that is fixable but it seems Netbird (the client) is taking UDP/51820 and this can clearly conflict. Happy to provide any additional information needed.

saavagebueno added the triage-needed label 2026-08-05 01:26:42 -04:00

saavagebueno commented

2026-08-05 01:26:42 -04:00

@Hutch79 commented on GitHub (Mar 4, 2026):

I just searched the pangolin docks for "gerbil port" and found this in the Unraid deployment guid:

By default we use a slightly different port than the standard WireGuard port to avoid conflicts with the built in WireGuard server in Unraid.

Right under the yellow "WireGuard port" section.

https://docs.pangolin.net/self-host/manual/unraid#2-configure-gerbil

So it seems like newer installs are already using a slightly different port to circumvent conflicts with other tool like Netbird, that use this port.

To fix the issue, you'd need to adjust your pangolin config.yaml and set the gerbil:start_port to something different, eg. 51822 and adjust your docker compose port mappings from 51820:51820/udp to 51822:51820/udp

@Hutch79 commented on GitHub (Mar 4, 2026): I just searched the pangolin docks for "gerbil port" and found this in the Unraid deployment guid: > By default we use a slightly different port than the standard WireGuard port to avoid conflicts with the built in WireGuard server in Unraid. Right under the yellow "WireGuard port" section. https://docs.pangolin.net/self-host/manual/unraid#2-configure-gerbil So it seems like newer installs are already using a slightly different port to circumvent conflicts with other tool like Netbird, that use this port. To fix the issue, you'd need to adjust your pangolin config.yaml and set the `gerbil:start_port` to something different, eg. 51822 and adjust your docker compose port mappings from `51820:51820/udp` to `51822:51820/udp`

saavagebueno commented

2026-08-05 01:26:42 -04:00

@Dimtar commented on GitHub (Mar 7, 2026):

@Hutch79 I appreciate your help but for now I am going to switch back to Tailscale. I don't want to edit Pangolin defaults just to get around an issue with Netbird that doesn't happen with Tailscale.

I am not sure why Netbird why needs 51820 open but hopefully they will resolve this one day.

@Dimtar commented on GitHub (Mar 7, 2026): @Hutch79 I appreciate your help but for now I am going to switch back to Tailscale. I don't want to edit Pangolin defaults just to get around an issue with Netbird that doesn't happen with Tailscale. I am not sure why Netbird why needs 51820 open but hopefully they will resolve this one day.

saavagebueno commented

2026-08-05 01:26:42 -04:00

@Hutch79 commented on GitHub (Mar 8, 2026):

According to the docs, the 51822 port already is the default since roughly 8 Months.
Changing it will have no effect on how Pangolin works.

Port conflicts are quite normal and there's no issue in changing them. This is in no way Netbird's or Pangolin's fault.
Tailscale probably uses another architecture then Netbird, so it works with them out of the box.

@Hutch79 commented on GitHub (Mar 8, 2026): According to the docs, the 51822 port already is the default since roughly 8 Months. Changing it will have no effect on how Pangolin works. Port conflicts are quite normal and there's no issue in changing them. This is in no way Netbird's or Pangolin's fault. Tailscale probably uses another architecture then Netbird, so it works with them out of the box.

saavagebueno commented

2026-08-05 01:26:42 -04:00

@Dimtar commented on GitHub (Mar 8, 2026):

I believe you’re referring to the Unraid documentation. The official installer and manual install still reference 51820
https://docs.pangolin.net/self-host/manual/docker-compose

Either way Tailscale manages to do what it needs to do without taking over port 51820 and I hope NetBird does the same one day.

@Dimtar commented on GitHub (Mar 8, 2026): I believe you’re referring to the Unraid documentation. The official installer and manual install still reference 51820 https://docs.pangolin.net/self-host/manual/docker-compose Either way Tailscale manages to do what it needs to do without taking over port 51820 and I hope NetBird does the same one day.

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Reference: DYNR/netbird#10636