Term:SSH [Secure SHell]

SSH is an acronym for Secure SHell, a remote command-line access mechanism. It’s refered to as “secure” because all comminications are encrypted.

SSH is most commonly available on Linux and other Unix-derived systems. It is used to access the equivalent of a Windows Command Prompt.

SSH is also unique in that it supports an additional form of authentication based on public-key encryption, and can be configured to require that only those in possession of the proper encryption key be allowed access.

SSH (Wikipedia)
Secure Shell
Communication protocol
Purposesecure connection, remote CLI
Developer(s)Tatu Ylönen, Internet Engineering Task Force (IETF)
Introduced1995
OSI layerApplication layer
Port(s)22
RFC(s)RFC 4250, RFC 4251, RFC 4252, RFC 4253, RFC 4254

Secure Shell (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network. Typical applications include remote command-line, login, and remote command execution, but any network service can be secured with SSH.

SSH provides a secure channel over an unsecured network by using a client–server architecture, connecting an SSH client application with an SSH server. The protocol specification distinguishes between two major versions, referred to as SSH-1 and SSH-2. The standard TCP port for SSH is 22. SSH is generally used to access Unix-like operating systems, but it can also be used on Microsoft Windows. Windows 10 uses OpenSSH as its default SSH client and SSH server.

SSH was designed as a replacement for Telnet and for unsecured remote shell protocols such as the Berkeley rsh and the related rlogin and rexec protocols. Those protocols send sensitive information, notably passwords, in plaintext, rendering them susceptible to interception and disclosure using packet analysis. The encryption used by SSH is intended to provide confidentiality and integrity of data over an unsecured network, such as the Internet.

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