I can't seem to get any servers to show up in Quake 4/Doom 3/COD 2 so I contacted Aspyr. They said this:
Ugh, I didn't know my MBP had a firewall. Could this be related to my router, which is connected to a Dell???
Thank you for contacting Aspyr Media.
It seems like you have a firewall issue. Check your firewall setting and make sure that ports are correct. For Quake 4 you need to have UDP Ports 28004, 27950 open.
We do not offer tech support for firewall.
You can also find some help for online play in the games Read Me files.
Have a nice day,
-Aspyr Media Technical Support
Ugh, I didn't know my MBP had a firewall. Could this be related to my router, which is connected to a Dell???