How do I open ports on a Mandrake 8.1 linux box? I have a network where one Mandrake 8.1 computer and a few Win32 computers are hooked up through a hub, and my cable modem is hooked up to the Linux computer. Now, I'm trying to create a Half-Life game server on my Linux computer, but it isn't showing up on the internet. I'm thinking my Linux router is blocking some ports I have to open up a couple ports and explicitly forward them to my Mandrake 8.1 computer. However I dont' know how to do this. I'm pretty much a newbie to Linux, how do I do this? Thanks.