TELNET is a
network protocol used on the
Internet or
local area networks to provide a bidirectional interactive text-oriented communications facility via a virtual
terminal connection. User data is interspersed in-band with TELNET control information in an 8-bit
byte oriented data connection over the
Transmission Control Protocol (TCP).
Telnet was developed in 1969 beginning with
RFC 15, extended in
RFC 854, and standardized as
Internet Engineering Task Force (IETF) Internet Standard
STD 8, one of the first Internet standards.
Historically, telnet provided access to a
command-line interface (usually, of an
operating system) on a remote host. Most network equipment and
operating systems with a
TCP/IP stack support a Telnet service for remote configuration (including systems based on
Windows NT). Because of security issues with Telnet, its use for this purpose has waned in favor of
SSH.
The term
telnet may also refer to the software that implements the client part of the protocol. Telnet client applications are available for virtually all
computer platforms.
Telnet is also used as a
verb.
To telnet means to establish a connection with the Telnet protocol, either with command line client or with a programmatic interface. For example, a common directive might be: "
To change your password, telnet to the server, login and run the passwd command." Most often, a user will be
telnetting to a
Unix-like server system or a network device such as a router and obtain a login prompt to a command line text interface or a character-based full-screen manager.