Nmap: The Hacking Standard
Nmap (Network Mapper) is arguably the single most important tool in a penetration tester's arsenal. It is free, open-source, and used for network discovery and security auditing.
What Nmap Does
- Host Discovery: Determining which hosts are currently running on a network.
- Port Scanning: Identifying open, closed, or filtered ports on the target.
- Service and Version Detection: Determining the exact application and version number running on an open port (e.g., 'nginx 1.14.0').
- OS Detection: Guessing the operating system of the target machine (Windows, Linux, etc.).
Nmap Installation and Availability
Nmap comes pre-installed on Kali Linux. It is also available for Windows and macOS, but it generally requires elevated privileges (root/administrator) to run powerful scans.