Nmap, short for Network Mapper, is a free, open-source network scanning tool used for network discovery and security auditing. Created by Gordon Lyon (pseudonym Fyodor Vaskovich), it employs raw IP packets to identify hosts, services, operating systems, and firewall configurations on a network. Nmap’s capabilities include port scanning (TCP and UDP), OS detection, version detection, and vulnerability scanning via its Nmap Scripting Engine (NSE), which supports Lua-based scripts for automation and advanced tasks. It’s widely used by network administrators for inventory management, service monitoring, and uptime tracking, as well as by cybersecurity professionals for penetration testing and vulnerability assessments. Nmap supports multiple platforms, including Linux, Windows, and macOS, and features a graphical interface called Zenmap for ease of use.