All of the communications between client and server, including the password entered to gain access, are encrypted to prevent outside parties from intercepting the data. A user might, for example, use an SSH client running on a Linux, Windows or macOS system to connect to the SSH server running on an Ubuntu system to gain access to a shell command-line prompt or to perform file transfers. As will be covered in “Ubuntu Remote Desktop Access with Vino”, SSH can also be used to provide a secure tunnel through which remote access to the GNOME desktop can be achieved over a network connection.Ī basic SSH configuration consists of a client (used on the computer establishing the connection) and a server (running on the system to which the connection is to be established). SSH is designed to allow secure remote access to systems for the purposes of gaining shell access and transferring files and data. This chapter will outline the steps to increase the security of an Ubuntu system by implementing key-based SSH authentication. This level of security is far from adequate and should be upgraded to SSH keybased authentication as soon as possible. When installed, SSH provides password protected and encrypted access to the system for the root account and any other users added during the installation phase. When an Ubuntu system is first installed, it is not configured by default to allow remote commandline access via Secure Shell (SSH) connections.