Wireguard tunnel intermittent connection drops

[doskel]

Hi there. I have a bit of an odd networking setup that uses a Wireguard server on a (Linux) VPS tunneling traffic to my FreeBSD server in my home.
While this worked fine for a while, a few days ago it began randomly (sometimes extremely frequently, sometimes working fine for a few hours) dropping the tunnel connection. Sometimes it comes back on its own, sometimes it requires a restart from a machine on the LAN that can connect without the tunnel (as the machine is up and on the network continuously).
I'm not really sure where to start monitoring for this, but there don't seem to be any route changes (checked with `route monitor`) and my home IP doesn't change. `dmesg` with Wireguard debug enabled also doesn't seem to have any information. Clocks are accurate on both machines, and the tunnel doesn't have this issue with other clients.
If anyone's got ideas on where to begin diagnosing, I'd appreciate pointers.
-doskel

 

[kjeacle]

Leave two pings running. One to the external address of the tunnel server and one on the inside of the tunnel. Check if anything happens to the external ping when the internal ping stops (perhaps there is a brief break in connectivity and the tunnel doesn't come back up). When the tunnel is down, run tcpdump on wg0 at both ends to see what is happening to the packets being sent into the tunnel. Worst case scenario, run a shell script or monitoring program that restarts the tunnel when ping fails.