Port Scanning Overview

Port scanning involves attempting to connect to ports on a target system to discover which ports are open and what services they correspond to. It is done by software that scans a range of ports, usually 0 to 65,536, and analyzes responses to determine whether ports are open, closed, or filtered. Common port scanning tools include Nmap and Netcat. While port scanning can be used maliciously for hacking, it is also used by system administrators to diagnose network issues.