NetStumbler (also known as Network Stumbler) is a tool for Windows that facilitates detection of Wireless LANs using the 802.11b, 802.11a and 802.11g WLAN standards. It runs on Microsoft Windows 98 and above. A trimmed-down version called MiniStumbler is available for Windows CE.

NetStumbler is commonly used for:

• Wardriving
• Verifying network configurations
• Finding locations with poor coverage in one’s WLAN
• Detecting causes of wireless interference
• Detecting unauthorized (”rogue”) access points
• Aiming directional antennas for long-haul WLAN links