SSH, or Secure Shell, is a network protocol which is used to connect to a web server and execute various tasks through a command line. The protocol is popular with many expert users, since the information transmitted over it is encrypted, so it can't be intercepted on the way by a third party. SSH access may be used 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 if the web server allows for it. If you have a virtual or a dedicated server, SSH may be used for just about anything - you could 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 allow you to use the protocol if your PC is running 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 even though many providers change it for security reasons.