Secure Shell, or SSH in short, is a remote connection protocol. It is meant for establishing secure connections to a remote computer. It uses advanced cryptographic algorithms, Eg. RSA., to encrypt data, unlike its predecessor telnet, which sends packets of data containing plain text, which may include passwords and compromise security. SSH is available for Linux, Windows and most other popular operating systems as well.

Open SSH is a free and open-source implementation of SSH protocol in Ubuntu and other Linux distributions. In this guide, we will see how to use Open SSH to enable SSH in Ubuntu 20.04.

Open SSH server and client are both available in standard Ubuntu 18.04 repository in the same package. To install Open SSH, run the following command in your terminal:

sudo apt install ssh

After installation, the SSH daemon ( sshd ) service, which is used for allowing remote connections from other computers, must be automatically started. To check its status, run:

service sshd status

Here, as we can see, the service is active. If it is not active, start it using:

sudo service sshd start

Once the service has started, remote computers can connect to your computer using SSH.

To connect to a remote computer from your computer, run:

ssh <username>@<domain_name/ip_address>

Note that the remote computer must have SSH installed and running and it must be either publicly accessible or accessible from your local network.

Make sure you check the manual page for SSH ( man ssh ) for further information.