The Security Mentor

Firewalls aren't magic. Those little boxes contain small computers running software that looks at the network traffic and decides what to let through.

You could run software like that on a regular personal computer. For a small network a firewall doesn't need much computing power. A computer from the early 90's can do the job just fine. Charities won't even accept computers that old any more. Their price is literally less than zero.

A free software package called Smoothwall Express, and another called IPCop, let you turn that computer into a firewall capable of protecting hundreds of computers, with extra features like VPN access, web content filtering and so on. The result looks competitive with thousand-dollar products from companies like Checkpoint. Near as I can tell, the only thing they're missing is support for central administration. You can even get commercial support if you get a paid version of Smoothwall.

Here's a review of Smoothwall Express if you're interested.

Does either product make sense for you? I'd say, only if you're a mid-sized organization with normal security needs. If you have a small network, you'll spend more on the electricity to run a PC than you would on a firewall appliance from Circuit City.