[andrewas]

That should do it. Thing is you have to make sure your PC has a static IP. If your brother is telling you to use port forwarding it probably already does, but if not its simple enough to do. Anyway, get your PCs local IP with ipconfig (run from a dosprompt), winipcfg or through the tcp/ip properties page for your LAN.

You don't have to worry about security unless overnet has a security exploit of its own. What your doing is saying that traffic on this particular port should be sent to your PC, theres no security issue apart from overnet and theres no way you can run this program without that risk. Now, if you were doing this with a DMZ, you would effectively be opening *every* port on your PC to the internet and it would be as if you had no firewall at all.