SSH, or Secure Shell, is a network protocol employed to connect to a server and perform various tasks through a command line. The protocol is employed by many experienced users, because the data transmitted over it is encrypted, so it cannot be intercepted on the way by a third party. SSH access may be used for lots of things depending on the type of web hosting account. With a shared hosting account, in particular, SSH is one of several ways to import/export a database or to upload a file when the server permits it. In case you have a virtual or a dedicated server, SSH could be used for just about anything - you may install software or restart specific services including the web server or the database server which run on the machine. SSH is employed largely with UNIX-like Systems, but there are clients that permit you to employ the protocol if your computer is working with a different OS too. The connection is established on TCP port 22 by default and the remote web server always listens for incoming connections on that port though lots of service providers change it for security reasons.