what ports do i need to open?

[ados]

I have a firewall in my router, and I am just wondering, what ports do I need opened to run a server, and how do I open them?

[Snyper]

start: 27005 end: 27020 UDP

[skeletor]

if the computer has a firewall.. just dmz it.. otherwise.. all you need open is 27015, or whatever the port of the server is.. and that would be tcp and udp..