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
Zenmap is a graphical front-end for the Nmap security scanner, making it ideal for network exploration and security auditing, while Skipfish is a web application security scanner designed for detecting vulnerabilities in web applications. Zenmap excels in network mapping and protocol support, whereas Skipfish is faster and better suited for web application assessment.