Introduction

The Internet is in the air. Some cities, such as Philadelphia, have municipal WiFi; many coffeehouses such as Starbucks and bookstores such as Barnes and Noble have wireless Internet services for their clientele. McDonald s restaurants provide WiFi hotspots with the Wayport service, and Boingo is another popular WiFi service provider. Wireless networks are everywhere, and their numbers continue to increase every day. If you are curious about the number of wireless LANs (WLANs) in your neighborhood or around your town, it is a simple matter to download some wardriving software and drive around with your laptop and a WiFi network card. If you have never done this, you might be surprised at the number of wireless access points (APs) that you find.You might also be surprised to find how many are wide open, with no encryption and perhaps even the default configuration just as the AP came out of the box. Of course, this book is geared toward the enterprise, but it is important to acknowledge the world of WLANs and their various roles in the different areas.

Many people feel as though a WLAN is, by its very nature, insecure.This is not necessarily the case, since many tools are available to help administrators secure their wireless networks. Of course, administrators need to understand the risks inherent with running a network over airwaves, and therefore they must be familiar with the options available for security.The same tools are available for wired LANs, such as switches, routers, and firewalls, and...