Transmission-daemon no connectivity over wireguard

waltmck commented 3 months ago

What is the issue?

I've been having some strange issues with connectivity when I run transmission-daemon inside of a network namespace over a wireguard interface. I am using the following setup:

Transmission runs inside of a systemd network namespace that only has access to a wireguard device wg0 (as well as a local loopback device). I can verify that only these are the only interfaces visible by running ifconfig -a.
For RPC, I am using systemd-socket-proxyd to forward 0.0.0.0:9091 outside of the netns to 127.0.0.1:9091 inside of the netns. This works fine and I am able to connect to the daemon successfully.
I changed routing rules so that all traffic originating within the netns is routed through the wg0 interface, as well as setting resolv.conf for the network namespace to make DNS work. I verified that both outgoing traffic routing and DNS are working successfully with dig and curl google.com from within the netns.
My VPN service provides a public IP address, so all ports are forwarded to wg0. I can verify that this is working correctly by stopping the transmission service, running nc -l 0.0.0.0 51413 within the netns, and then connecting with nc -v <VPN public ipv4> 51413 (this works for any other port too).

Unfortunately, when I try to actually torrent one of my beloved Linux ISOs, Transmission fails as if it has no internet connection whatsoever (see logs). I tried opening port 51413 and running Transmission outside of the wireguard network namespace and was able to torrent successfully, so I have narrowed the problem down to the wireguard interface. Since I am using Nix, I am able to share my entire config reproducibly: here is the config that works without using a wireguard VPN while here is the config that fails to connect.

I don't have much networking experience, but I'm really puzzled as to why Transmission would fail when as far as I can tell packets are being routed correctly. Could anyone help identify the problem here, or is it a bug?

Thank you!

Which application of Transmission?

transmission-daemon

Which version of Transmission?

transmission-daemon 3.00

kiwixz commented 3 months ago

Logs basically says you can't establish connections, DNS is failing and it can't connect to the trackers. You probably cant ping/curl or anything from the netns ? or maybe it is because of the address you bind the socket to ?

tearfur commented 3 months ago

You can run Transmission with the environment variable TR_CURL_VERBOSE set, then you will see curl debug logs alongside the Transmission logs. Maybe that will tell you what's wrong.

waltmck commented 2 months ago

This strangely seems to have started working again without me changing my configuration. Since I am no longer able to replicate, I suppose this should be completed.

transmission / transmission