Nmap Cheat Sheet

Nmap (Network Mapper) is the industry-standard open-source tool for network discovery and security auditing, trusted by penetration testers, system administrators, and security professionals worldwide since its 1997 release by Gordon Lyon (Fyodor). Nmap excels at host discovery, port scanning, service version detection, OS fingerprinting, and executing custom security scripts through the Nmap Scripting Engine (NSE)—all while offering sophisticated firewall evasion techniques and flexible timing controls to balance speed against stealth. One key insight: Nmap's power multiplies when you combine scan types, timing templates, and NSE scripts strategically—a basic SYN scan paired with version detection and the right timing template can reveal far more than the sum of its parts, making every flag choice a tactical decision in how loud or quiet you want your reconnaissance to be.