Nmap

/ɛn.mæp/ · Noun · Security & Infosec · Origin: 1997

Definitions

Nmap (Network Mapper) is a free, open-source tool used for network discovery, security auditing, and port scanning. Created by Gordon Lyon (known as Fyodor) and first released in 1997, Nmap sends specially crafted packets to target hosts and analyzes the responses to determine which ports are open, what services and versions are running, what operating system is in use, and what types of firewalls or packet filters are deployed. Nmap supports numerous scan techniques including TCP SYN (half-open), TCP connect, UDP, FIN, and idle scans, each with different stealth and accuracy tradeoffs. The Nmap Scripting Engine (NSE) extends its capabilities with hundreds of scripts for vulnerability detection, brute force testing, and service enumeration. Nmap is an essential tool for network administrators, penetration testers, and security professionals. It runs on all major operating systems and has appeared in numerous movies and TV shows depicting hacking, including The Matrix Reloaded.
In plain English: A tool that scans a network to find what computers and services are running — the digital equivalent of knocking on every door in a building to see who's home.

1997: Gordon 'Fyodor' Lyon publishes Nmap in Phrack Magazine issue 51, initially as a simple port scanner
2003: Nmap appears in 'The Matrix Reloaded' — Trinity uses it to scan a power grid, making it the most famous hacking tool in cinema
2009: Nmap Scripting Engine (NSE) transforms it from a scanner into a full vulnerability assessment platform