SSH Definition

Secure Shell (also commonly referred to as SSH) is a network protocol that provides secure access to remote computers by encrypting all the communications between clients and servers. In other words, SSH allows you to build a so-called SSH tunnel where at one end the data is encrypted and sent, while at the other end, it is received and decrypted. Through the tunnel, all of the data that moves is encrypted.

There are currently two versions of the SSH protocol: SSH1 and SSH2. The latter is widely considered as the more secure one. SSH is a very versatile protocol that can be used for a variety of tasks such as remote server administration, accessing remote files, and debugging network problems.

One of the main advantages of SSH is that it encrypts all traffic between the client and the server, making it difficult for unauthorized users to intercept the connection.

SSH is usually included in most Linux-based and Mac OS X distributions and can also be installed on Windows systems. There are many different SSH clients, both free and commercial. One of the most popular SSH clients is PuTTY.

One can establish a secure SSH connection only as long as there are two systems involved in the process: a client and a server.

1. A client is a local device from which the user can perform remote control.
2. A server is a managed remote machine. The machine is controlled by various commands that are managed by the command interpreter (aka the shell).

It is important to understand that you can connect to the server only if special software called Deamon is installed on it. Without the Deamon, the user will not be able to log in to the server and will not be able to use secure SSH ports when exchanging data.