Nmap is a free and open source network scanning and audit tool available at https://Nmap.org/. This tool is one of the most important components of a network-level security audit, as it allows the user to monitor or observe the network-level posture of a host by providing data about open ports and services running on these ports. The Nmap tool also allows interaction with these services and the running of various scripts using Nmap Script Engine (NSE). The following command is the syntax to perform TCP syn full port scanning on the host 127.0.0.1:
Nmap -sS -p1-65535 127.0.0.1
We will be looking into recipes for the usage of the Nmap tool in further chapters.