SSH, or Secure Shell, is a network protocol employed to connect to a server and execute different tasks via a command line. The protocol is popular with many experienced users, as the data transmitted over it is encrypted, so it can't be intercepted on the way by a 3rd party. SSH access could be employed for a number of things based on the type of website hosting account. With a shared hosting account, for example, SSH is one of the ways to import/export a database or to upload a file when the web server permits it. If you have a virtual or a dedicated server, SSH can be used for practically anything - you may install software or restart certain services such as the web server or the database server that run on the machine. SSH is employed largely with UNIX-like Systems, but there are clients that permit you to use the protocol if your computer system is using a different OS too. The connection is established on TCP port 22 by default and the remote hosting server always listens for incoming connections on that port although a lot of service providers change it for security reasons.