Multiple LAN computers can't connect to online game [SOLVED]

[Squeeler]

I'm trying to get a VPN working so that two people can play online FAF games together from the same LAN. We have it working with port forwarding, using different UDP ports, where each person can join a separate FAF game. But to play in the same game, I am trying to use a VPN on one machine so that they have different external IP addresses, otherwise they can't connect to each other. With a VPN (VPNbook), it doesn't see any FAF games and can't host a game.

Offline FA LAN games work (without VPN). But we're trying to connect to online FAF games.

Anyone know how to configure this to work? What VPN settings are needed?

Alternatively, what router settings could I try that would allow the machines to connect using external IP addresses?

[Mielus]

turn upnp off, and use different port forwards for each PC, normally faf uses port UDP 6112, then you also need to forward UDP 6111 or 6113 (I am not sure if it is one above the base port or below, so I do both)

So for one PC, you forward ports UDP 6111 6112 6113 and set the gameport to 6112
For the other PC, you forward ports UDP 6121 6122 6123 and set the gameport to 6122

Airvpn can do portforwards, you can get 5 consecutive port forwards there, that should work with the same principle

[nine2]

I do this with three pcs, without vpn, No problem

In faf options I give them a different port. Upnp does the rest

[Squeeler]

Thank you! These two suggestions worked. Port forwarding on its own with a range (6111:6113 forwarded to 6112, and different ports for the other machine) didn't work, but it does when both FAF clients are set to use upnp. Thank you!!!!!

[Squeeler]

Sad face. This worked one single time today, but isn't working anymore. Even after rebooting both machines and router. Double-checked settings, IP addresses, routing table, etc. Nothing has changed since it worked the first time, but it won't work now.
I found an article about my Asus router (AC-68u) and something called "nat acceleration" / "Cut-through forwarding" not being compatible with port-forwarding.
https://routerguide.net/nat-acceleration-on-or-off/
So I shut that off in the router, and it still doesn't work.
Tried increasing the range of ports forwarded (ex, 6110:6116 forwarded to 6112, for one machine) and that made no difference. Tried forwarding both TCP and UDP packets for each range, rather than just UPD. Nope.
Any suggestions? Any idea why this would have worked only once??

[Squeeler]

WORKS ! Finally. one machine had to clear all its data; cache, settings, and game files. Works with upnp on both machines.