SSH, or Secure Shell, is a network protocol employed to connect to a server and execute various tasks via a command line. The protocol is popular with many expert users, for the reason that the information transmitted over it is encrypted, so it may not be intercepted on the way by a 3rd party. SSH access could be employed for a lot of things depending on the type of hosting account. With a shared hosting account, in particular, SSH is among the ways to import/export a database or to upload a file in case the web server allows for it. If you have a virtual or a dedicated server, SSH can be used for practically everything - you may install software or restart particular services such as the web server or the database server that run on the machine. SSH is used mostly with UNIX-like Systems, but there are clients that enable you to employ the protocol if your computer system is using a different Operating System as well. The connection is established on TCP port 22 by default and the remote hosting server always listens for incoming connections on that port though a lot of providers change it for security reasons.