A terminal emulation protocol used on the Internet and TCP/IP-based networks. A Telnet program allows a user at a terminal or PC to log in to a remote computer and run a program and execute other Unix commands. Originally developed for ARPAnet, Telnet is a common utility in the TCP/IP protocol suite, but it is not secure and transfers commands in the clear. Secure shell (SSH) provides an encrypted alternative that is widely used (see SSH). See also Telenet.