Angry IP Scanner OR IP Scan is an cross-platform network scanner designed to be fast ip scan and simple to use. It scans IP addresses and ports for a given IP range as well as has many other features.
The program uses separate threads for each scanned address to reduce scanning speed. It can also display NetBIOS information: computer name, workgroup, currently logged user and MAC address.
It runs on Linux, Windows, and Mac OS X, possibly supporting other platforms as well.
It is widely used by network administrators and just curious users around the world, including large and small enterprises, banks, and government agencies.