Back in the day when I was a Computer Information Specialist, networks were being built and the internet was just ramping up. In those days you had to be creative. A tool that I used at the time to scan and monitor my network that consisted of a campus of buildings was Angry IP Scanner. After all these years, Angry IP Scanner still surfaces here at ‘What’s On My PC” to tell me, “I am still around”…
Angry IP Scanner (or simply ipscan) is an open-source and cross-platform network scanner designed to be fast and simple to use. It scans IP addresses and ports as well as has many other features.
It is widely used by network administrators and just curious users around the world, including large and small enterprises, banks, and government agencies.
It runs on Linux, Windows, and Mac OS X, possibly supporting other platforms as well.
Source: Angry IP Scanner