How to disable password authentication in SSH

SSH is by default configured to allow logins via both password and public key.

Users would choose bad passwords and might not manage their passwords properly. This could be a security risk thus you might want to disable password authentication on your SSH servers. The alternative is to configure public key authentication for your users.

You can disable password authentication by disabling PasswordAuthentication directive for your SSH server.

Steps to disable password authentication in SSH:

1. Launch your preferred terminal application.
2. Open sshd configuration file using favourite text editor.

   $ sudo vi /etc/ssh/sshd_config
   [sudo] password for user:

3. Search for PasswordAuthentication and set the option to no.

   PasswordAuthentication no

   Add the line if it doesn't already exist and remove the # at the beginning of the line if exists.

4. Reload or restart SSH server service.

   $ sudo systemctl restart sshd