What is Nmap? Why you need this network mapper

Network administrators, IT managers and security professionals face a never-ending battle, constantly checking on what exactly is running on their networks and the vulnerabilities that lurk within. While there is a wealth of monitoring utilities available for network mapping and security auditing, nothing beats Nmap’s combination of versatility and usability, making it the widely acknowledged de facto standard.

What is Nmap?

Nmap, short for Network Mapper, is a free, open-source tool for vulnerability scanning and network discovery. Network administrators use Nmap to identify what devices are running on their systems, discovering hosts that are available and the services they offer, finding open ports and detecting security risks.

Nmap can be used to monitor single hosts as well as vast networks that encompass hundreds of thousands of devices and multitudes of subnets.

Though Nmap has evolved over the years and is extremely flexible, at heart it’s a port-scan tool, gathering information by sending raw packets to system ports. It listens for responses and determines whether ports are open, closed or filtered in some way by, for example, a firewall. Other terms used for port scanning include port discovery or enumeration.