From the doc: 'Scans a range of IP address for a certain open port. It attempts to connect to each IP on the specified port, and if the connection is a success, adds the IP to a list. You can then connect up to the port, and transfer data... If you want to find hosts with an open telnet port. Telnet ports are used by businesses, for users to log in to. Scan for open Telnet ports, then use Telnet.exe to connect up to them, and commence hacking. Trojan horses can be scanned for, then when they are found, they can be connected to with the trojan horse client.'
hakscan.exe