Wireless Home Networking - Index of

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Part IV: Using a Wireless Network
We find sniffer programs to be handy because they’re a great way to take a
quick survey of our surroundings when we’re on the road. For example, Pat
was recently staying at a hotel that belonged to a chain partnered with
Wayport, but Wayport hadn’t officially started offering service yet — and the
hotel staff was clueless. No problem! A quick session using the Network
Stumbler software (see the following subsection), and — lo and behold! —
the Wayport access point in the lobby was up and running. With a quick flip
of the wallet (to pull out his prepaid card), Pat was up and running on
high-speed wireless Internet. Take that, dial-up!
Network sniffer programs are also a good way to help you evaluate the security
of your own network. In fact, they’re the main reason why the developers
of Network Stumbler created the program. After you implement some of the
security steps we discuss in Chapter 9, you can fire up your favorite sniffer
program and see whether you’ve been successful.
Netstumbler.com
The granddaddy of wireless network sniffer programs is Network Stumbler
(www.netstumbler.com), which is a Windows program (it works with
Windows 95, 98, Me, 2000, and XP) that connects to the PC Card network
adapter in your laptop and lets you survey the airwaves for available Wi-Fi
access points. Network Stumbler lists all available access points and gives
you relatively detailed information about things such as the SSID and Media
Access Control (MAC) address of the AP, whether WEP is enabled, and the
relative power of the signal. You can even combine Network Stumbler with a
GPS card in your laptop to figure out exactly where you and the access point
are located.
Network Stumbler doesn’t work with every Wi-Fi card. You can find a list of
compatible cards on the Netstumbler.com Web site.
Figure 16-2 shows Network Stumbler in action in Pat’s house, tracking down
his two access points (and one of his neighbor’s APs, too!).
If you use a Pocket PC handheld computer, the folks at Netstumbler.com have
a program for you: Mini Stumbler, available at the same Web site (www.netstumbler.com).
A similar program called MacStumbler (www.macstumbler.
com) is available for Mac OS X computers.
In fact, a growing number of these network sniffer programs are available,
and most of them are free to download. You can find a list at the Personal
Telco Project at http://wiki.personaltelco.net/index.cgi/WirelessSniffer.