Restricting a computer's access to the Internet

[Ironside]

I have got four computers connected to a router (BT Voyager 2100) how can I restrict one of those computers from accessing the Internet? I want to be able to turn the access on and off from just one computer (not the computer that is going to be restricted)

[rkoenig]

Hello, that question is more or less covered in this thread

Scroll down to Andy's posting, and look into the squid proxy server, either windows or linux version.