Reverse Telnet (sometimes called direct Telnet) is the initiation of a Telnet session from a computer system to one of its remote users. Usually, a Telnet session is initiated by a user who wishes to access and share resources on a remote computer system. The user must have permission and is prompted to provide a user name and password. Reverse Telnet is when the host computer initiates a Telnet session instead of accepting one.
Reverse Telnet is typically used by a system administrator to configure or to troubleshoot a remote computer.