Nmap

Nmap (Network Mapper) is a free and open-source network discovery and security auditing tool that uses raw IP packets to determine what hosts are available on a network, what services and versions those hosts are offering, what operating systems they are running, and what type of packet filters or firewalls are in use across the infrastructure. The tool provides comprehensive network scanning capabilities for security professionals and system administrators to perform tasks including network inventory management, service upgrade scheduling, vulnerability assessment, penetration testing preparation, and monitoring host or service uptime through both command-line and graphical interfaces with the Zenmap GUI and advanced features like the Nmap Scripting Engine for automated detection and exploitation testing.