Secure Shell or SSH

Secure Shell or SSH refers to both network protocol and programs those helps to connect to a network with a remote device through command line safely. Previously we wrote about differences between FTP and Secure Shell or SSH and Common Internet Protocols. This time we will go in to a bit details on Secure Shell or SSH as it seems to us, these commonly used terminologies are what visitors want to know about in plain English.

What is Secure Shell or SSH

Secure Shell or SSH is used to get connected with a remote machine through command line, using a program that is, on running a local machine. The output of the remote computer and input from keyboard of remote computer is send through these Secure Shell or SSH programs. This is like sitting in front of the remote console, which can be used for remote maintenance of server. The newer version of Secure Shell is SSH-2 protocol which offers additional features such as file transfer via SFTP.

Usages  of Secure Shell or SSH

Newer version of Secure Shell or SSH 2 provides secure, authenticated and encrypted connection between two hosts over an insecure network. Thus Secure Shell serves as a substitute for rlogin, telnet and rsh – all uses to send passwords unencrypted compared with Secure Shell. Secure copy (SCP) is evolved from RCP protocol over Secure Shell.

To summarize the usages of Secure Shell or SSH

• SFTP and SCP provide cryptographically secure alternative to FTP and RCP using new version of SSH.
• Secure System Administration, Secure Remote Command Execution are done through SSH.

Client can use Secure Shell either via public key authentication system using a private key pair whose public key is stored on the server or can access using simple password authentication. Enabling the public-key authentication enables the client to login without the user interaction to Secure Shell or SSH servers and importantly. without requiring the password to be stored. To further secure the Secure Shell, private keys are protected with a password.

UNIX based operating system like Mac OS X or most Linux distributions do not need any extra software for executing command through Secure Shell. For Windows SSH Client like PuTTy for executing commands and WinnSCP to access SFTP are used.