Another Port Problem

[Phoenix2]

Here is the problem. I have 2 computers, with a wireless GI-624 router. One is connected via lan, and the other is connected wirelessly. The computer connected via lan is the one hosting my Source Dedicated server, and the other is used to play on and rcon the server. Whenever I restart the server, though, my IP is always the same, but the port changes to a random number everytime. This is becoming a real hassle because I can't keep the server on all the time, and whenever my clan members try to join using their favorites, it will always say the server isn't responding. This forces them to have to hunt down the server using the name in the browser. Very annoying.
Can somebody please tell me how I can make the server always use the 27015 port. I have tried the port thingy on portforward.com, but I think I messed up because it didn't work.

Thanks

[cryotek]

Are you running any firewalls? Have you tried to DMZ the host that runs the srcds?

[Phoenix2]

I am running Windows Firewall. I don't know how to "dmz the host," so I probably haven't.

[cryotek]

Try disabling windows firewall, go into your routers web interface and around the same area for port forwarding should be a tab or an option for running dmz.