Telnet
Telnet is a command-line tool that provides access to a command-line interface on a remote host. As it uses Transmission Control Protocol (TCP), it may also be used to test TCP connectivity with a remote host. Because of serious security concerns when using Telnet over an open network such as the Internet, its use for this purpose has waned significantly in favor of SSH.[1] The following activities will show you how to use Telnet.