I use Tailscale as a means to connect with the various VMs/LXC containers etc in my Homelab. Until now I’ve been a Windows desktop user, with TS continuously active, and with Private Internet Access (PIA) VPN installed as well. I don’t often have PIA (Private Internet Access VPN) activated, but I have IPs placed in PIA’s split tunnel exceptions for when I do connect (provided by TS but I`m unable to link them here). When PIA and TS are activated (with the PIA exceptions added) all worked as expected.
I’m now trying (for the nth time) to run a Linux desktop OS. When I install TS first, all connections are great. As soon as I install (but not connect to) PIA, I am unable to connect to any device over the TS network. The TS admin page shows my laptop as connected, but for all intents and purposes, it is not. If I correctly uninstall PIA via the GUI client app, the TS network comes alive again.
FWIW, I tried adding the aforementioned exceptions to the PIA app, which did nothing, and I also used the Wireguard protocol for PIA.
I gather that PIA is probably trying to dominate the connections and override TS, but I can’t for the life of me figure this out.
Just a question, if you know the answer, the problem is then 2 Wireguard interfaces can’t be running at any given moment? Is that the issue? It doesn’t explain the mere presence of PIA’s app causing interference though.
It is definitely possible to have multiple Wireguard interfaces present (and active) at a time.
One potential issue may be that PIA and Tailscale were fighting over a port, where PIA won, and Tailscale stopped working. Another thing could be DNS/routing/whatever changes that PIA made conflicted with Tailscale.
So here what I think is the problem, your PIA client is off but you have split tunnel enabled. You told the local connection to use the tunnel but since the PIA tunnel is off - functionally “closed”, the internet traffic cannot pass, because the split is after the tunnel entrance, behind a closed connection.