SSH, or Secure Shell, is a network protocol used to connect to a web server and carry out various tasks via a command line. The protocol is preferred by many experienced users, as the data 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 variety of things with regards to 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 website hosting server permits it. If you have a virtual or a dedicated server, SSH could be used for pretty much anything - you could install software or restart certain services including the web server or the database server that run on the machine. SSH is employed primarily with UNIX-like Operating Systems, but there are clients that allow you to use the protocol if your personal computer is working with a different OS as well. The connection is made on TCP port 22 by default and the remote server always listens for incoming connections on that port though a number of providers change it for security reasons.