Win 2K and Multiplayer game help?

[Shack70]

Ok, I have Win98Se and Win 2K installed for dual boot. I cna play Halflife an dcounterstrike just fine on both OS's and I cna get multiplayer to work in Win98Se no prob. When i try to play Multiplayer in Win 2k, I can't connect. The port 27015. Does Win 2K have ports blocked somehow? How do I open them up? I am also running a Linksys 4 port router, but I believe it is Win2k and not the router since I can get out and play on Win98SE. Any suggestions?

Thanks in advance