You will need to find out what port is being used by your pc to set this up through the firewall. The easy way to do this is to temporarily bypass your firewall by either setting your machine up to be a DMZ host, or by simply plugging your connection from your DSL or Cable modem directly to your pc (you will need to reboot to obtain a proper IP after this).

Once that is done, launch the game in multiplayer mode, in a window if possible, or minimize to windows.

Go to a command propmpt (dos prompt) and type in "netstat -a". This will give you a listing of all of your current listening, open, and established sessions on your pc. You should be able to pick out which one of these G2 is using. It will look something like this:

Local++++++++++++++++++Remote++++++++++++State
dave:1728++++++ bobby.anywhere.net:8315+++++Established

The port you will need is the local one. In this example it is 1728.

Now, reconnect everything as it was before you started and reboot your pc to obtain your LAN (local) IP address (usually a 192.168.0.x.

On your firewall software or gateway/router, you can specify that any request on port 1728 be routed to your local IP (the 192.168.0.x address).

That's it. I have done this for many applications and it works well.

-Dave