Nmap
Free network scanner for discovering hosts, open ports, running services and operating systems across networks of any size.
- Pricing
- Free
- Platforms
- LinuxWindowsmacOS
- Licence
- Open source
- Reviewed
- Last reviewed 24 September 2026
What it is
Nmap ("Network Mapper") is a long-established command-line network scanner, with Zenmap as its graphical interface. The suite also includes Ncat for data transfer, Ndiff for comparing scans, Nping for packet generation, and the Nmap Scripting Engine (NSE) for custom checks.
What it helps with
Mapping which hosts are up, which ports are open, which services and versions are running, and what firewalls are in place. NSE scripts extend it to vulnerability checks and service enumeration.
Who it's for
Penetration testers, network and system administrators, and security teams doing inventory or audits.
Worth knowing
Scan only networks you are authorised to test. Nmap describes itself as free and open source; its licence is the Nmap Public Source License (NPSL), which is not an OSI-approved licence.