quantum resistant tunnel may cause wireguard connections to not work

[aAsm321]

Is it a bug?

• I know this is an issue with the app, and contacting Mullvad support is not relevant.

I have checked if others have reported this already

• I have checked the issue tracker to see if others have reported similar issues.

Current Behavior

I had quantum tunneling on "Automatic", and everything else on default.
The app will try to connect wireguard, the connection is established successfully. However, there is no actual internet access. The app will eventually time out the VPN connection and try connecting again. The situation repeats itself.

Expected Behavior

When trying to connect via wireguard and an issue arises as a result of quantum tunneling, the "automatic" option in quantum tunneling app should act accordingly.

Switching quantum tunneling to "off" fixes the issue

Steps to Reproduce

This issue is likely difficult to reproduce because it only occurs on a heavily filtered corporate internet. Nonetheless, my main concern is improving the "automatic" functionality for the "quantum tunneling" feature.

Anyways, to reproduce the issue,
1- Set quantum tunneling to "Automatic"
2- Try to initiate a VPN connection with wireguard

Failure Logs

No response

Operating system version

Linux mint 22

Mullvad VPN app version

2024.7 (version maybe unrelated)

Additional Information

I can confirm that this fixed my wireguard connection issue on 2 systems.

[MarkusPettersson98]

Hi! You mention that you sit on a heavily filtered corporate internet which I would like to dig a bit deeper into. When you manage to connect successfully, which feature indicators show up on the main app screen? Also, does it work with PQ if you also enable some kind of obfuscation? If you have the time and energy, please try with both Shadowsocks and UDP2TCP. The latter is likely to perform pretty badly, but it could be an interesting datapoint 😊

[aAsm321]

Quantum tunneling setting	Obfuscation setting	Time to connect (1)	Time to connect (2)	Time to connect (3)	Internet connection working? (all trails)	Connection stability (all trails)	Feature indicators (separated by commas, all trails)
Automatic	Off	2 minutes 38 seconds	2 minutes 40 seconds	23 seconds	No	Connection is lost after few seconds	Quantum resistance
Automatic	Shadowsocks	DNF, (still connecting after 5 minutes)	DNF, (still connecting after 5 minutes)	DNF, (still connecting after 5 minutes)	N/A	N/A	Quantum resistance, Obfuscation
Automatic	UDP-over-TCP	DNF, (still connecting after 5 minutes)	DNF, (still connecting after 5 minutes)	DNF, (still connecting after 5 minutes)	N/A	N/A	Quantum resistance, Obfuscation
Off	Off	5 seconds	5 seconds	5 seconds	Yes	Stable	N/A
Off	Shadowsocks	0 seconds (immediately)	0 seconds (immediately)	0 seconds (immediately)	No	Connection is lost after few seconds	Obfuscation
Off	UDP-over-TCP	0 seconds (immediately)	0 seconds (immediately)	0 seconds (immediately)	No	Connection is lost after few seconds	Obfuscation

• Ports for any setting were set to Automatic

[MarkusPettersson98]

That's amazing, thanks a lot! I guess the last thing to look into are the daemon logs then 😊 Would you mind pasting them here? If you extract them by navigating to Settings > Support > Report a problem in the app and click View app logs we make sure to redact sensitive information, so it is fine to paste online. If you don't wish to do that, please send a problem report on the aforementioned app page and make sure to mention this issue. Then our support team will forward the logs to us privately. Thanks!

[aAsm321]

You are welcome! I have sent the logs to the support team.
Thank you for being very professional and polite!

[dvdplm]

FWIW the suggested workaround here also solves my connection issues (identical to OP's): app fails to connect on default settings, turning off quantum resistant tunnels solves the problem.

[IssuesPlease]

Just wanted to add that I'm having difficulty with 2024.8 shutting down despite lockdown mode & killswitch both being ON. I'm also using quantum-resistant. Mullvad shuts itself down randomly after about a half hour and exposes the machine to open internet traffic. And this happens invariably when the machine goes to sleep but wakes back up. On Linux Mint OS. Very scary. Hope disabling quantum-resistant will solve the problem. Otherwise, relying on Mullvad VPN will be itself a security risk.

[MarkusPettersson98]

Just wanted to add that I'm having difficulty with 2024.8 shutting down despite lockdown mode & killswitch both being ON. I'm also using quantum-resistant. Mullvad shuts itself down randomly after about a half hour and exposes the machine to open internet traffic. And this happens invariably when the machine goes to sleep but wakes back up. On Linux Mint OS. Very scary. Hope disabling quantum-resistant will solve the problem. Otherwise, relying on Mullvad VPN will be itself a security risk.

If that's the case, please assist us in finding the root cause of this by forwarding logs to our support team or opening up a new GitHub issue where we can have a more focused discussion (since it goes beyond the scope of this issue). We take unwanted traffic leaks very seriously, and they always have the highest priority from us.

You can forward anonymized logs from within the app by going to Settings > Support > Report a problem. If you forward the logs to our support team, please refer to this issue. That way, they will be able to forward the logs to us developers in an efficient manner.

Stay safe 💛