Chapter 6. Building Your Own Access Point

Wi-Fi access points are inexpensive, because they are now accepted as commodity hardware. You can buy them at discount stores, warehouse clubs, and probably your local gas station. Models with many features and support for 802.11g can now be purchased for well under $100.

Why then would you want to build your own access point? Aside from the usual geek reason ("because you can," a.k.a. "why even ask?"), there are many practical reasons:

• Make use of old or surplus PC hardware. An effective access point can be built with a 486/33 and 16 MB of RAM. Many commercial access points are not any more powerful inside. Don't know what to do with that old Pentium? Stick a radio card in it and unwire your house.

• Take advantage of a complete Linux installation. Run an iptables firewall to protect your network, build a web caching server, and set up intrusion detection. If you build a Linux-based access point, you can do almost anything with it.

• Run a customized Linux kernel on off-the-shelf hardware. Wireless access point/routers from Linksys and other manufacturers are actually running Linux kernels inside. Several groups of people have put out alternative firmware for these units. You can build your own custom firmware if you want.

These are only a few good reasons to build your own access point. In order to get started, you need some hardware, a Linux distribution, and some configuration basics. We cover each in turn .