Linux Networking Cookbook

3.1. Assembling a Linux Firewall Box Problem

You want to build your own Internet firewall box for your cable or DSL Internet line, on ordinary x86 hardware, using your favorite Linux distribution. You want Internet connection sharing and a firewall, and you need to know what hardware components to use. You already have installation disks, or some other method of installing the operating system.

Solution

The Linux distribution you want to use determines your hardware requirements. Some distributions require more horsepower than others, so don't assume you can use some feeble old antique PC without checking. This chapter's Introduction lists a number of specialized firewall distributions.

You'll need these items to build and set up your firewall box:

• A PC with at least two Ethernet interfaces

• A second PC and a crossover cable for testing

You'll connect only the LAN interface until your firewall has been installed and configured.

Go ahead and install your chosen Linux distribution, then follow the recipes in this chapter to configure your network interfaces and firewall.

Install net-tools and Nmap because you will use them a lot in this chapter. They should also be installed on a second PC for testing. Debian users will also need to install the ifrename package.

Discussion

Repurposing old PCs saves money and keeps them out of landfills. They can be customized any way you like. They also make dandy test-and-practice boxes. The drawbacks are size, noise, power consumption, and the fact that they ...