[Tutorial] How to play multiplayer using Tunngle

[barbanium]

If you guys can see each other in GH and can see each others chat, I don't think port forwarding Tunngle will do anything.

Nor enabling DMZ in your router settings. I've played MHP3rd in Tunngle with 3 other players WITHOUT enabling DMZ. I think that's only appropriate for connecting to Coldbird's Prometheus server.

BUT if really do think these might solve your problem, I guess there's no harm to give them a try.