Nmap was released 19 years ago on September 1. Seems like it has been around for ever. Nmap (Network Mapper) is a security scanner and open source software originally written by Gordon Lyon used to discover hosts and services on a computer network. Nmap first appeared in an article in Phrack magazine back in 1997. Instead of cake, nmap project celebrating open source style with a new release!
Nmap was designed to rapidly scan large networks, although it works fine against single hosts. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. While Nmap is commonly used for security audits, many systems and network administrators find it useful for routine tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime.
I love Nmap project and happy belated bday. This tutorial provides 30 examples of nmap for sysadmin and infosec professionals.