NetBird DNS Forwarded tries to listen on a well-known mDNS port 5353

[nazarewk]

Describe the problem

NetBird DNS Forwarded tries to listen on a well-known mDNS port 5353.

systemd-resolved already claims the port (0.0.0.0:5353 & [::]:5353) as soon as you set MulticastDNS=true.

This is probably true for all (or at least most) multicast DNS servers.

To Reproduce

n/a

Expected behavior

NetBird DNS forwarder listens (or at least retries with) a custom port, which does not match any of the well-known ports used for other purposes.

Are you using NetBird Cloud?

Yes, n/a

NetBird version

0.40.0

Is any other VPN software installed?

no

Debug output

2025-04-17T14:33:33+02:00 ERRO client/internal/dnsfwd/manager.go:51: failed to start DNS forwarder, err: listen udp :5353: bind: address already in use

Screenshots

n/a

Additional context

Add any other context about the problem here.

Have you tried these troubleshooting steps?

• 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