Telnet stands for TErminaL over NETwork and is defined in RFC 854. Telnet is the way you can access someone else's computer, assuming they have given you permission. With Telnet, you log on as a regular user with whatever privileges you may have been granted to the specific application and data on that computer. With Telnet Ethernet options can be configured. For security reasons the usual Telnet Port 23 is not used.