How to use the Nmap scanning tool

Nmap is a very powerful network scanning tool, mainly used to scan computers or devices on the network, check their open ports and services, and determine their operating system and application versions. The following are the basic usage methods and common parameters of the Nmap tool:

1. Basic usage method:

   nmap [Scan Type] [Options] {target specification}
   

2. Common parameters:

   • -sS: Use TCP SYN scanning.
   • -sT: Use TCP connect() to scan.
   • -sU: Use UDP to scan.
   • -sN: Use TCP Null scan.
   • -sF: Scan with TCP FIN.
   • -sX: Scan using TCP Xmas.
   • -O: OS fingerprinting of the target.
   • -A: Simultaneously perform multiple scans such as operating system fingerprinting and port scanning.
   • -n: Do not resolve the host name, directly use the IP address to scan.
   • -v: Output detailed information.
   • -p: Scan the specified port, which can be a single port, multiple ports or a port range.
   • -iL: Specifies to read target information from a file.

The above are some commonly used parameters, you can use nmap -hthe command to view all available parameter options.