Nmap

Nmap ("Network Mapper")

Screenshots

Hunter's comment

Nmap tool is one of the most powerful tools used in penetration testing process, its function is that it performs a careful examination of any system or network and by gathering information about the target, such as open ports (port), and if it is in a firewall, loyalty, and type of system
The tool has a ZEMAP graphical interface and is an essential tool in any penetration testing system.

Link

https://nmap.org/