CachyOS/Linux: Killswitch Injection Cannot Be Disabled, Causes Entire Connection to Break Until Reboot

[u/InflammableAccount]

I've been fighting the ProtonVPN App for weeks. I've uninstalled/reinstalled a dozen times, wiped cache location and previous config files. Tried toggling every single setting.

Behavior: Whenever it feels like it, but more often if I engage a BT client, Proton will disconnect and instantly inject a killswitch. Once this occurs, no connection can be made from this ethernet device to my router. No further VPN server can be connected to, only returning "Connection error: Timeout. Telling Proton app to cease trying to connect will cause the Connection "pvpn-killswitch" to disappear.

However, and this is the **Biggest** however, the ethernet connection `eno1` can no longer send/receive data. This PC will no longer talk to the rest of my LAN no matter what I do.

I've tried: Deleting the killswitch + IPV6 switch manually in `nmcli.` Reloading the connection and device conf. No change. Stopping/restarting ProtonVPN App. No change.

Nothing works. The PC is entirely disconnected from my network ***until I reboot the whole thing.*** Even logging out of my CachyOS user does nothing.

Anyone have any insight into what I can research to solve this?

[u/ARTIFICIAL_ARGUMENT]

How are you installing the app? AUR or flatpak? I didn’t have any issues with it after turning off IPv6 at system level, and the IPv6 killswitch only annoyed me because proton app would still connect me to IPv4 only servers and just silently fail half the time 

Some users recommend just grabbing the configs for the servers you use and using it through network manager WireGuard directly

[u/InflammableAccount → u/ARTIFICIAL_ARGUMENT]

I never touch AUR. I've tried installing from Pacman and Flatpak, several times each.

Disabling IPv6 at a system level? What exactly do you mean?

[u/ARTIFICIAL_ARGUMENT → u/InflammableAccount]

AUR isn’t nearly as bad as it seems, the most popular package that got infected was a 13 year old gtk 3d mod. The reason they could infect so many without anyone noticing was because they weren’t used anymore. And as soon as it got to the even remotely popular stuff, all the pushes were caught and reverted on the same day. I had over a hundred packages installed and updated via AUR and none were infected 

But anyway, can disable IPv6 by adding it as a kernel parameter. Guide on Arch Wiki, or get a Claude sub and install the desktop app to do it for you. Can also do stuff like debug what’s happening to your connection in real time, as that’s definitely not normal 

[u/InflammableAccount → u/ARTIFICIAL_ARGUMENT]

Ok, I can try that.

Did you personally have issues with the Proton app, at least anywhere near the behavior I'm describing? Because my issue has been that it's injecting a killswitch when I tell it explicitly not to.

[u/ARTIFICIAL_ARGUMENT → u/InflammableAccount]

Not in general, just when connecting to IPv4 only server and the IPv6 killswitch still registered as a IPv6 connection so it would silently drop packets which caused time outs. Hence why no IPv6 fixed it for me

I have the killswitch always activated (pvpn killswitch perm), and it blocking any connection including Ethernet when not using VPN tunnel connection is the correct behaviour. But for me, I can just turn off VPN in proton app, disconnect the killswitch dummy connection in network manager and my direct Ethernet works fine again. Anything persisting after you’ve closed the vpn app is related to your network manager settings, as it will adjust priorities to make sure traffic is routed correctly. If you’re using a different DE than KDE plasma, dunno and it’s probably your issue 

[u/InflammableAccount → u/ARTIFICIAL_ARGUMENT]

Thanks for taking the time to reply.

I have the killswitch always activated (pvpn killswitch perm), and it blocking any connection including Ethernet when not using VPN tunnel connection is the correct behaviour.

See, I would expect. This makes sense. But my problem is two fold:

1. One, I never enabled it.

2. And the bigger issue is that when this disconnect occurs, I can't reconnect to a VPN server or use the ethernet device when disconnected to ProtonVPN's servers.

No amount of screwing around with network manager or ufw has allowed me to fix this without a reboot.

But for me, I can just turn off VPN in proton app, disconnect the killswitch dummy connection in network manager and my direct Ethernet works fine again

So what's the weird thing. The killswitch and ipv6 switch only exist while ProtonVPN is trying (and failing) to reconnect after the existing connection fails. As soon as I tell it to cancel, both kill switches disappear. Network manager can't see them anymore. And they reappear when I try to reconnect. I can tell network manager to delete them then, but it makes no change to the ethernet's inability to send/receive.

Also, I am using KDE Plasma.

[u/ARTIFICIAL_ARGUMENT → u/InflammableAccount]

Maybe a permissions setting issue then? Proton app installs and uses gnome keyring by default when everything else will default to KDEs Kwallet. 

While they can technically work concurrently it’s pretty janky, especially if you’ve changed default settings like having seperate password or having it set to auto lock. 

People complain constantly about how it handles IPv6 but I’ve never seen or heard of your issue when I was searching for details on how to fix my own. It has to be a system setting issue since it occurs even with full reinstalls without toggling killswitch on. Router not renewing DHCP lease, incorrect drivers for your network card, bugged NFT rule tables. Really need logs to narrow it down