Netgame problem

My friend and I can't join each other's games. We even tried to join via IP. However, we can each join a game someone else hosts. My friend claims to also have other people join his games (not many, but some), and I never had someone join a game I hosted. Does anyone know what me or my friend can do to fix this?

Are you on the same local area network?

If not, if you're under a router you will have to forward the UDP port 5029 to the local IP of the computer hosting the server - otherwise nobody outside the network will be able to join.

http://www.portforward.com/ <-- Has a guide specifically for SRB2 I believe. It's a different process for every router.