Zenmap vs. Tenable Nessus

Zenmap is the official graphical user interface (GUI) for the Nmap Security Scanner, designed to make network scanning accessible for both beginners and experienced users. This multi-platform, free, and open-source application supports operating systems such as Linux, Windows, Mac OS X, and BSD. Zenmap simplifies the process of network discovery and security auditing by providing an intuitive interface to Nmap's powerful features.

Built for security practitioners, by security professionals, Nessus products by Tenable are the de-facto industry standard for vulnerability assessment. Nessus performs point-in-time assessments to help security professionals quickly and easily identify and fix vulnerabilities, including software flaws, missing patches, malware, and misconfigurations - across a variety of operating systems, devices, and applications.