SSH, or Secure Shell, is a network protocol employed to connect to a web server and conduct different tasks through a command line. The protocol is preferred by many skilled users, as the information transmitted over it is encrypted, so it can't be intercepted on the way by a third party. SSH access could be employed for a variety of things with regards to the type of website hosting account. With a shared hosting account, for instance, SSH is one of the ways to import/export a database or to upload a file when the hosting server allows it. If you have a virtual or a dedicated server, SSH could be used for practically everything - you could install software or restart certain services like the web server or the database server which run on the machine. SSH is used primarily with UNIX-like Systems, but there are clients that permit you to employ the protocol if your PC is using a different OS as well. The connection is made on TCP port 22 by default and the remote hosting server always listens for incoming connections on that port even though lots of providers change it for security reasons.