Simon Thorneycroft and Jonathan Hodgson

801.11x Wireless Troubleshooting

I was asked today about troubleshooting wi-fi issues, we ran through the usual basics:

• Check connectivity by connecting via patch cable to the router directly
• Check the status light indicators
• Remove the WEP/WPA security until you get things working and then secure it up
• Look for other devices in the same area
• Change the name, SSID from the standard out of the box settings
• Try using the wireless card drivers instead of the Windows XP standard configuration
• Try a different make of wireless router, ie. Cisco, Linksys, Netgear, etc.
• and so on...

Also pointed to a useful tool called Netstumbler, which can help you identify available networks.

So to answer your question, unless you have a specific reason for changing it, I would suggest you keep your wireless channel configured for the manufacturer's default settings. If, however, you must change it, for the best performance I would suggest trying to use one of the other non-overlapping channels first: Channels one, six, and eleven. Other then interference issues, there really is no other reason or advantage to selecting another channel.

It also reminded me of the insecure.org list of top hacking tools, which has some basic port scanner, etc. utilities. For more commerical tools, eEye digital security have a product called Retina security scanner and Iris network analyser which is a fanastic tool for analysing network traffic.

If you are thinking of securing a wireless network in a corporate environment the Microsoft Technet series, "How Microsoft does IT" has an in-depth article on 'Enterprise Deployment of Secure 802.11 Networks Using Microsoft Windows' and 'Troubleshooting Microsoft Windows XP-based Wireless Networks in the Small Office or Home Office'.