The tool is a web interface for the well known Nmap, which is executed with the proper parameters in order to provide speed and accuracy.
The scanning is done by sending packets to each port and listening for replies. The scanning technique is called ‘SYN scan’, which sends TCP SYN packets to each port. If a port responds with SYN-ACK, it is flagged as open and a RST is sent back by our tool. This way there is no full TCP connection established with the target host.