In this interesting and exceptionally thorough “how-to” article, ZDNet editors Eric House and Henry Kingman guide you through the process of creating a Linux firewall using a 486 based PC. House and Kingman cover everything you need to know and do — from where to download the software (Linux Router Project), to how to configure and maintain the resulting system. While the article assumes that you're teaching an old dog (a no-longer-needed 486 PC) a new trick, there's nothing preventing you from using the information provided to develop an Internet Firewall Appliance product based on a compact single-board computer, such as one of the many available 486-based PC/104 CPUs with built-in Ethernet.

House & Kingman write . . .

“Everybody's talking about using Linux to turn an old 486 into a router/firewall for a home or small office network. This article offers step-by-step instructions for setting up such a device using Open Source software from the Linux Router Project (LRP). If you have an Internet connection with a single static IP address, a 486 box with a working floppy drive and at least 12MB of RAM, two NICs and a hub, you have everything you need to provide safe Internet connectivity for your whole network.”

“What is LRP? In brief, it's a minimalist Linux distribution that boots from a single floppy disk. Since the disk can be write-protected using the corner tab lock, there is no chance for anyone to damage your installation over the Internet. On the off-chance the firewall is breached, you can return the machine to its original state by simply cycling the power to reboot.”

“LRP runs atop a filesystem mounted on a RAM-disk. Because everything is in RAM, it runs very quickly. A 486 should be more than able to keep pace with a T-1 or better.”

“After setup, LRP machines can be run 'headless' — without a monitor. For the home network, it may be desirable to remove the hard drive. (In any case, it won't be mounted while LRP is running.) After the drive is gone you may safely disconnect the fan for quieter operation.”

“This article assumes some basic knowledge of Linux and enough networking savvy to configure two computers together on a LAN. For additional information on LRP, consult the LRP documentation or mailing list.”

“Let's get started by taking a closer look at exactly what we'll need . . . “

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