Nmap
Open Source
Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool.
Angry IP Scanner
Open Source
IP scanner is a fast, friendly, extensible, free and open-source IP scanner to scan addresses and ports in any range.
Zenmap
Open Source
Zenmap is the official cross-platform GUI for the Nmap Security Scanner. It is free and runs on Linux, Windows, Mac OS X, etc.
InvGate Assets
Commercial
InvGate Assets has a solid feature set when it comes to IT asset management, adequately covering both hardware and software.
Compare Softperfect Network Scanner - NetScan with alternatives
Compare Nmap and Softperfect Network Scanner - NetScan and decide which is most suitable for you.
Compare Zenmap and Softperfect Network Scanner - NetScan and decide which is most suitable for you.
Compare Angry IP Scanner and Softperfect Network Scanner - NetScan and decide which is most suitable for you.
Compare InvGate Assets and Softperfect Network Scanner - NetScan and decide which is most suitable for you.