SSH, also known as Secure Shell or Secure Socket Shell, is a network protocol or operating network services securely over an unsecured network.
Ubuntu ships with OpenSSH in its universe repository. OpenSSH consists of ssh server, sftp server, and ssh-agent, and it allows remote operations using ssh, scp, and sftp.
How to Install OpenSSH in Ubuntu 19.10:
The OpenSSH client package is installed by default in Ubuntu. To access to current machine via ssh protocol, install the server package via following commands.
1. Open terminal either via Ctrl+Alt+T keyboard shortcut or by searching for “terminal” from application menu.
2. When terminal opens, run command to install OpenSSH service:
sudo apt install openssh-server
Input your password (no asterisk feedback while typing) when it prompts and hit Enter.
3. Once installed, SSH starts automatically in background.
To change SSH setting, e.g., listening port, root access, etc. run command:
sudo gedit /etc/ssh/sshd_config
The command opens the configuration file via Gedit (For Ubuntu Server you may use nano instead).
For more about the configuration file, see the manual.
Finally remember to restart SSH service to apply changes:
sudo systemctl restart ssh.service
And you can check the ssh daemon status via command:
sudo systemctl status ssh.service