This is a favorite tool of windows user to scan wireless network and found open WEP Access Point. although it can not crack WEP crack, I think this tool is useful.
What is NetStumbler?
NetStumbler is a tool for Windows that allows you to detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g. It has many uses:
* Verify that your network is set up the way you intended.
* Find locations with poor coverage in your WLAN.
* Detect other networks that may be causing interference on your network.
* Detect unauthorized "rogue" access points in your workplace.
* Help aim directional antennas for long-haul WLAN links.
* Use it recreationally for WarDriving.
The requirements for NetStumbler are somewhat complex and depend on hardware, firmware versions, driver versions and operating system. The best way to see if it works on your system is to try it.
Some configurations have been extensively tested and are known to work. These are detailed at http://www.stumbler.net/compat. If your configuration works but is not listed, or is listed but does not work, please follow the instructions on the web site.
The following are rules of thumb that you can follow in case you cannot reach the web site for some reason.
* This version of NetStumbler requires Windows 2000, Windows XP, or better.
* The Proxim models 8410-WD and 8420-WD are known to work. The 8410-WD has also been sold as the Dell TrueMobile 1150, Compaq WL110, Avaya Wireless 802.11b PC Card, and others.
* Most cards based on the Intersil Prism/Prism2 chip set also work.
* Most 802.11b, 802.11a and 802.11g wireless LAN adapters should work on Windows XP. Some may work on Windows 2000 too. Many of them report inaccurate Signal strength, and if using the "NDIS 5.1" card access method then Noise level will not be reported. This includes cards based on Atheros, Atmel, Broadcom, Cisco and Centrino chip sets.
* I cannot help you figure out what chip set is in any given card.
If you have an old WaveLAN/IEEE card then please note that the WaveLAN firmware (version 4.X and below) does not work with NetStumbler. If your card has this version, you are advised to upgrade to the latest version available from Proxim's web site. This will also ensure compatibility with the 802.11b standard.
Other Requirements and Compatibility Issues
* Your card must be configured in such a way that it can be seen by the management software that came with the card.
* The Microsoft-provided Orinoco drivers that come with Windows 2000 do not work with NetStumbler. Please visit Windows Update or www.proxim.com and upgrade to the latest drivers.
* When NetStumbler is in "auto reconfigure" mode (the default), it will occasionally disconnect you from your network. This enables it to perform its scans accurately, and is not a bug.
* If you have the WLAN card configured to connect to a specific SSID, NetStumbler may not report any accees points other than those that have that SSID. Configure your card with a blank SSID or, if a blank one is not permitted, "ANY" (without quotes).
click here to read more about NetStumbler.