Is this a known problem? Ubuntu/Linux changing wifi network causes zerotier problems (sometimes)?

[Dug]

During a test this morning, while zerotier was running on my Ubuntu 22.10 laptop I changed wifi from my local at home wifi to my tethered phone so I could jump to a network outside of my home network.

I noticed that I could not connect to any of my zerotier peers. I had to stop and restart the zerotier service to get it to work again. Changing back to my home wifi worked without having to restart.

Is this a known issue? I’ve searched and found some similar reports with other OS’s, but not anything exactly the same.

I’ve also noticed when connecting a wired USB ethernet to the laptop that even though the metric of the USB ethernet device is lower (and thus higher priority) than the wireless device metric, the connections to peers (some? All? IDK) continue to be routed via the wireless device.

thanks!

[oskari.rauta]

This is most likely a firewalling issue. I noticed same behaviour on another distribution. When new connection was made available, firewall restart was triggered and existing connections were killed and upnpd made rules disappeared.

One possible solution would be to statically define used port (default zerotier port is 9993) and open it for udp on your firewall.