what is SSH???

SSH, also known as Secure Socket Shell, is a network protocol that provides administrators with a secure way to access a remote computer. SSH also refers to the suite of utilities that implement the protocol. Secure Shell provides strong authentication and secureencrypted data communications between two computers connecting over an insecure network such as the Internet. SSH is widely used by network administrators for managing systems and applications remotely, allowing them to log in to another computer over a network, execute commands and move files from one computer to another.

SSH can refer both to the cryptographic network protocoland to the suite of utilities that implement that protocol. SSH uses the client-server model, connecting a secure shell clientapplication, the end at which the session is displayed, with an SSHserver, the end at which the session runs.

Apart from Microsoft Windows, SSH software is included by default on most operating systems. SSH also supports tunneling, forwarding arbitraryTCP ports and X11 connections while file transfer can be accomplished using the associated secure file transfer or secure copy (SCP) protocols. An SSH server, by default, listens on the standard TCP port 22.

The SSH suite comprises three utilities -- slogin, ssh and scp -- that are secure versions of the earlier insecure UNIX utilities,rlogin, rsh, and rcp. SSH usespublic-key cryptography to authenticate the remote computer and allow the remote computer to authenticate the user, if necessary.