After spending WAY too long troubleshooting this I'm coming here for help.

 

I'm trying to setup wireguard VPN tunnels for docker containers to use

 

• I'm using a firefox docker container to test the VPN connection
• I have a mullvad tunnel setup on WG2 that works flawlessly
  • I switch the Firefox containers network to WG2, I can curl ifconfig.io in the terminal and I can go to google.com within the browser. The IP address also reflects the mullvad IP
• I am attempting to switch to Surfshark and I have generated a .conf file on the surfshark website and imported it and it is setup as WG3
• I switch the firefox containers network to WG3. I can successfully curl ifconfig.io but Firefox can not access google.com. I also tried just going to 1.1.1.1 in firefox to troubleshoot dns issues and that also didnt work

Some other notes:

• I loaded the surfshark .conf into the Windows Wireguard app and the connection DOES work.
• The surfshark wireguard settings match Mullvad's in every way (save for the settings clearly unique to the respective service) EXCEPT the "peer allowed ips" is "0.0.0.0/0, ::0/0" for mullvad and only "0.0.0.0/0" for surfshark
  • I did try matching surfshark to mullvad and that didnt work either. I've since reset it back to the defaults
• I also tried other containers by firefox. None of them have internet access using WG3. They all work using WG2 (mullvad)

My hunch is this has something to do with DNS settings due to a number of my tests above but I'm too much of a novice to really put my finger on it... Any thoughts/advice is appreciated!

Edited January 8, 20242 yr by jmenur

Don't know if this will help or not

 

Looks like a great topic to dig through. Will search through it now. Appreciated

To anyone coming across this in the future the solution described in the future this post was the fix that was needed (MTU and MSS clamping)