Secure shell

Secure shell or SSH is both a program and a network protocol for logging into and executing commands on a remote computer. It is intended to replace rlogin[?], telnet and rsh[?], and provides secure encrypted communications between two untrusted hosts over an insecure network. X11 connections and arbitrary TCP/IP ports can also be forwarded over the secure channel.

The program is a common Unix shell program, but there exists implementations for most modern platforms, including Microsoft Windows (where one of the most popular is PuTTY).

A later version of the protocol was released under the name SSH2.

OpenSSH is an open source implementation of SSH. Corkscrew is a tool enabling the user to run SSH over HTTPS proxy servers.

An IETF working group, secsh, is currently in the process of standardizing the protocol.

External links

• IETF working group (http://www.ietf.org/html.charters/secsh-charter)
• PuTTY home page (http://www.chiark.greenend.org.uk/~sgtatham/putty/)

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This article (or an earlier version of it) contains material from FOLDOC, used with permission.