2) Nmap: Network Mapper
Reduced as Nmap is a flexible device for network security, in addition to being a free and open source. Administrators use Nmap for system inventory, decide on open ports, monitor management review schedules, and observe the uptime of the central system or administration. Nmap uses unprocessed IP packets in novel ways to determine which hosts are available on the network, what services (name and version of the application) they offer, what operating systems (and versions of the operating system) they run, what kind of packet firewall there are Use and many other features.
Nmap was named “Security Product of the Year” by Linux Journal, Info World, LinuxQuestions.Org and Codetalker Digest.