Computers on a wireless network are at risk of attack from anyone nearby. Since there are not the same physical bounds to network access that there are in a wired network, clients are at a much higher risk of attacks. Linux is a powerful, complex operating system. Properly configured, a Linux host can withstand sustained attacks from dedicated attackers. Unfortunately, a poorly configured Linux machine can be a dangerous weapon for an attacker and a liability to you as an individual.
Wireless support in Linux has progressed dramatically over the past several years. FreeBSD used to be the operating system of choice for WLAN usage, but the support now available under Linux makes it a great operating system for wireless networking. Linux supports many common 802.11b cards. Many vendors developing 802.11a and 802.11g equipment are developing Linux drivers at the same time as their Windows drivers. Other vendors are deploying embedded Linux systems with wireless support.
Unless otherwise noted, the examples given in this chapter are performed on RedHat Linux 7.2 with kernel 2.4.18. The examples should work on most recent Linux distributions, but may require small changes to the scripts or file locations. For more information regarding RedHat Linux, see http://www.redhat.com. For more information on kernel 2.4.18, see http://www.kernel.org.