Proton VPN (paid, with port forwarding) - port shows up as open on slsk website, but still looks closed in program - anyone got Proton VPN fully working?

[exostalker]

Hey, wondering if anyone got Nicotine+ working fully with Proton VPN (paid, with port forwarding)?

When I indicate the supposedly open port from Proton VPN in the client, even though soulseek website for checking if port is open says it is - I can definitely tell it isn't working that way in the program itself.

This is quickly revealed while testing through another computer of mine with another soulseek client as I can tell there with my static connection from ISP there (since I know for certain there that if I open them there they are open - if open ports on that other computer there, I can find the files - if closed, can't - meaning that my VPN client computer has closed ports too) ; as well as one buddy of mine in the list clearly has their ports closed as I can't browse them with VPN at all (and yet I can as soon as I turn off the VPN and use my simple static connection with open ports).
Another obvious giveaway being that when I left the program running through the night, only a few people downloaded anything - yet if I connect with my static IP without VPN and with ports actually open, I get 5x that number of people starting to download stuff in 10-15minute window alone.

Any feedback/suggestions would be welcome - I think I tried the usual troubleshooting tips already though - did try binding the interface to Proton VPN and unbinding, checking upnp and unchecking etc (gives out UPnP: Failed to forward external port XXXXX: No UPnP devices found error if checked, behaviour itself doesnt seem to change at all though)

[slook]

You have outlined a reason why changes to the NAT-PMP and UPnP modules are required, because I don't think the NAT-PMP/UPnP function is capable of dealing with interface binding, it only gets forwarding route from a default gateway, so this could lead to a conflict, in such a case of there being a virtual private network interface, whereby the desired route is not on the system default gateway.

I was working on this the other day to make it respect the binding interface setting, see slook@435f30f in my development branch:
https://github.com/slook/nicotine-plus/tree/portmapper-gateway-fallback-netstat

However I am unable to fully test it, because I am behind a public NAT for which I do not have any possibility of port forwarding. Are you able to check out my development branch? You could run it from a local Git folder, or you can install an Artifact from packaging run at link:
https://github.com/slook/nicotine-plus/actions/runs/8214087851

For these testing and troubleshooting tasks it will be useful to activate the "Miscellaneous" log category in debug logging, it will reveal more details while establishing an initial connection with your router, or your providers virtual router.

Alternatively, you might have to turn the NAT-PMP/UPnP option off in Preferences > Network, in order to avoid it from interfering with your manual port forwarding router settings.

[exostalker]

I tested that ^ and sadly same thing. Also same for turning off NAT-PMP/UPnP, already tried it, same with it enabled or disabled.

[slook]

Did you test it with a network interface binding in Nicotine+ Preferences? That is the only case where it might make any difference.

Also with the extra debug logging in my development build, perhaps you can verify exactly which interface is used.

[slook]

Please open a terminal and provide the outputs of the following commands:

• cat /proc/net/route
• netstat -rn

[slook]

netstat -rn

[exostalker]

Yeah that above is the "netstat -rn"

[slook]

The code in my development version is flawed, it won't work on Windows. A different approach will be required.

For now it is probably necessary to disable UPnP/NAT-PMP and specify an interface binding adapter in Preferences.

Additionally, some other configuration may be required in the OS, such as firewall or routing of the forwarded port.

[toineenzo]

If you're running N+ inside Docker, make sure to check out https://github.com/qdm12/gluetun . It makes it really easy to correctly implement VPN with docker container and N+