For any network, big or small, network monitoring and security is a very essential task. Regular monitoring of the network is important to protect the systems from attacks and also keeps viruses and malware out of the network.

Nmap, short for Network Mapper, is a free and open source tool for network monitoring and is the most versatile tool for system/network administrators. Nmap can be used to perform security scans, explore the network, find open ports on the remote system, and perform network audits.