HOW TO: Build your own network firewall
Network appliances don’t always offer all the firewalling features a user needs — you know, the 
advanced port blocking and security procedures we’d like to keep our little home network fiefdoms secure. In today’s How-To we’ll show you how to build a firewall out of an old PC with a live Linux CD and some spare ethernet cards. It’s the perfect use for that machine with the dead hard drive (or no hard drive at all).
For this How-To you’ll need:
* A suitable PC, with a CD-ROM and USB port - we suggest a Pentium II
* At least two Ethernet ports (onboard + a second card or similar)
* A blank CD-R to burn the system CD
* USB thumb drive, floppy disk or hard drive. How-To: Build your own network firewall - Engadget