NetBird Clients Stuck on Relay – Unable to Establish Direct P2P Connections
I have a NetBird server running inside Docker on an Ubuntu VM. Clients are unable to establish direct peer-to-peer (P2P) connections and are instead routing all traffic through relays. This is causing significant performance issues, especially when using an exit node, where clients experience only 20% of expected speed.
What I Have Checked So Far:
UDP is open and working – Confirmed via tcpdump, showing UDP traffic on port 3478.
Coturn is running inside Docker – It is configured via /home/netbird/turnserver.conf.
Firewall rules allow UDP traffic – No DROP or REJECT rules exist for UDP 3478 or UDP 51820.
Coturn is listening on UDP 3478 – But clients still don’t use direct P2P.
Clients are still relaying all traffic – netbird status shows Relays: 3/3 Available.
NetBird logs confirm all traffic is using relays instead of direct connections.
Coturn’s STUN/TURN server is not discoverable –
nslookup -q=SRV _stun._udp.5.9.113.196 failed.
Clients are not registering with STUN/TURN.
docker logs netbird-coturn-1 shows no clear errors, but relays remain active.
What I Need Help With:
Why are NetBird clients unable to establish direct UDP connections, despite UDP being open?
Why is Coturn’s STUN/TURN server not being discovered by clients?
How can I force NetBird to prioritize direct P2P over relays?
Are there any additional Coturn or NetBird configuration changes needed?
Any insights or suggestions would be greatly appreciated!
What I Have Checked So Far:
UDP is open and working – Confirmed via tcpdump, showing UDP traffic on port 3478. Coturn is running inside Docker – It is configured via /home/netbird/turnserver.conf. Firewall rules allow UDP traffic – No DROP or REJECT rules exist for UDP 3478 or UDP 51820. Coturn is listening on UDP 3478 – But clients still don’t use direct P2P. Clients are still relaying all traffic – netbird status shows Relays: 3/3 Available. NetBird logs confirm all traffic is using relays instead of direct connections. Coturn’s STUN/TURN server is not discoverable –nslookup -q=SRV _stun._udp.5.9.113.196 failed.
Clients are not registering with STUN/TURN.
docker logs netbird-coturn-1 shows no clear errors, but relays remain active.
What I Need Help With:
Why are NetBird clients unable to establish direct UDP connections, despite UDP being open? Why is Coturn’s STUN/TURN server not being discovered by clients? How can I force NetBird to prioritize direct P2P over relays? Are there any additional Coturn or NetBird configuration changes needed?Any insights or suggestions would be greatly appreciated!
Solution
For the MTU for some reason, specifically for the wt0 interface, the MTU was set to 1500 so I had to reduce it until I saw it work well.
For the P2P to finally work properly, I just turned off the external firewall for my exit node VM that's on my cloud provider, rookie mistake. I am using UFW and it has the usual ports open for netbird. I just had to reconnect it and it worked.
For the P2P to finally work properly, I just turned off the external firewall for my exit node VM that's on my cloud provider, rookie mistake. I am using UFW and it has the usual ports open for netbird. I just had to reconnect it and it worked.
