A port scan can assist you to figure out whether ports on a network are open, listening, or closed. This is used by administrators to test network security and the firewall strength of the system. It is a common reconnaissance tool for hackers to discover the weak point in a system in order to get in.
The following are some of the most frequent basic port scanning techniques:
- UDP
- Ping scan
- TCP connect
- TCP half-open
- Stealth scanning