Telnet is a protocol for connecting from one computer to another using a text-based command line interface. Telnet connections can be made over a local network or over the Internet.

Making a Telnet connection requires a client application on the local computer (where commands are typed) and a Telnet server running on the remote computer (where the commands are carried out). Once connected, the command line on the client will be treated as if it were on the server, accepting input and displaying output.

A telnet client connected to a telnet server
A telnet client connected to a telnet server

The Telnet protocol was first developed in 1969 to enable computer users at universities and research institutions to use their room-sized mainframe computers from smaller, more conveniently-located computer terminals. Since it was designed for use on a local network, before the Internet even existed, it does not encrypt its traffic. Information, including user names and passwords, is sent as plain text and can be easily read if intercepted by a third party, so Telnet is no longer widely used. Other protocols, like SSH, are now used instead.

Updated September 22, 2022 by Brian P.
Reviewed by Per C.

quizTest Your Knowledge

Which of the following is most likely to only have a single webpage?

Dynamic website
Personal blog
WordPress site
Parked domain
Correct! Incorrect!     View the Parked Domain definition.
More Quizzes →

The Tech Terms Computer Dictionary

The definition of Telnet on this page is an original definition written by the team. If you would like to reference this page or cite this definition, please use the green citation links above.

The goal of is to explain computer terminology in a way that is easy to understand. We strive for simplicity and accuracy with every definition we publish. If you have feedback about this definition or would like to suggest a new technical term, please contact us.

Sign up for the free TechTerms Newsletter

How often would you like to receive an email?

You can unsubscribe or change your frequency setting at any time using the links available in each email.

Questions? Please contact us.