Zenmap is the official cross-platform GUI for the Nmap Security Scanner. It is free and runs on Linux, Windows, Mac OS X, etc. Developed by Gordon Lyon
License: Open Source
Nmap is a robust command-line tool favored by network professionals for its extensive scanning capabilities and flexibility. Zenmap, on the other hand, is a graphical frontend for Nmap, making it more accessible for beginners while still providing essential Nmap features.