Port Forwarding
From OPU Wiki
This is a guide to setup port forwarding to allow you to play Multiplayer via Direct IP when you are behind a router or any other sort of Firewall. Make sure you know your Router Model Number and Username and Password.
First, direct your browser to http://192.168.1.1
If you are prompted for a username and password, then you have sucessfully found your router configuration page. If not, visit portforward.com (http://www.portforward.com/routers.htm) and find your router model number. (This may even have complete instructions for portforwarding)
To be continued
P.S. The ports you need are 47800 to join games and the range 47776 - 47807 to host games
