Analyze This

eLABorations: Tools such as Yellowjacket take the sting out of designing, troubleshooting and securing 802.11b WLANs

Setting up a Wireless LAN at home can be as easy as powering up your new 802.11x access point and plugging it into your Internet router. Most home users probably wont worry about security unless they have a tenacious, nosey neighbor.

But WLAN implementations can be a challenge for IT managers who dont have the right tools. How do you make sure you have enough access points for your clients? Where do you place the hubs and access points to optimize signal strength? Security is also a big concern. How do you sniff out rogue access points to prevent your network from being compromised by hackers?

Simple handheld wireless analyzers, such as the Yellowjacket from Berkeley Varitronics, can answer these questions. Sites that need an inexpensive tool to design, troubleshoot and secure their 802.11b WLANs should invest in these analyzers if they havent already done so.

The Yellowjacket is a wireless receiver module packaged with Compaqs iPAQ Pocket PC for analyzing 2.4GHz WLANs. The Yellowjacket receiver can measure all 14 DSSS (Direct Sequence Spread Spectrum) channels used in 802.11b wireless networks, and provides useful information including access points SSID (Service Set Identifier), PER (Packet Error Rate) and signal strengths. (Fluke Networks is also planning to release a WLAN analyzer coupled with an iPAQ.)

Using the Yellowjacket, IT managers can look for vulnerabilities and prevent the companys WLAN from being compromised by hackers.

The Yellowjacket takes a unique approach to alert administrators to wireless network hack attempts via authorized access points or client access cards. It scans the network topology and lists WLAN traffic for all 14 DSSS channels with corresponding MAC (media access control) addresses and SSIDs. If a hacker tries to access the network, the Yellowjacket sends out an alert and provides the hackers MAC address, SSID and signal strength, allowing administrators to track down the security breach.

The Yellowjacket can also be equipped with an optional 9 dBi direction finding antenna, and goes into "Geiger Mode" to pin point RF energy sources. Geiger Mode is also useful for surveying the WLAN for interference.

Technical Analyst Francis Chu can be reached at