The word Kismet is not to be confused with the Kismet Dice game or Kismet DVD. Kismet is an open source tool for network security professionals that performs packet sniffing and intrusion detection. Kismet is preferred to be run on Linux but is compatible with Windows, Mac OSX and BSD systems. Without leaving fingerprints, Kismet can monitor all data that is comes across, not just the data from the access point. This makes is a powerful stealth tool for law enforcement.
Primarily a client to server application, Kismet can also act as a standalone application and as a drone, meaning it can monitor individual machines across a network and forward them to the server of your choice.
When running as drones, each instance of Kismet requires separate configuration files. This allows you to forward all gathered data from all drones to a single server log and monitor for wireless intrusion as well. This is perfect for networks with multiple access points.
As with most packet sniffers, Kismet is a bit difficult for newbies but offers extensive documentation and a large community of users who help each other over hurdles. The interface is minimalistic, but extremely powerful. Kismet is more powerful than I make it sound here, but the more experience you have with network security, the more features you will recognize. However, even with a basic understanding of network security, one can easily use Kismet for network intrusion detection. Download Kismet Free and see what others rant about.