SSH server's default configuration is to allow both password and public key logins.

PasswordAuthentication
Specifies whether password authentication is allowed. The default is yes.

Some admins consider password login to be insecure due to improper password management by the users. As such, you might want to disable password authentication on your SSH servers and force users to authenticate using other methods such as the public key.

You can enable or disable password authentication by configuring PasswordAuthentication directive in your SSH server.

Steps to enable or disable password login 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 to disable PasswordAuthentication method and yes to enable.
    PasswordAuthentication no

    Add the line if it doesn't already exist and remove # at the beginning of the line if it exists.
    Set it to yes to allow password authentication method and no to disallow.

    Make sure another authentication method is enabled and tested before disabling the password authentication method.

  4. Reload or restart SSH server service.
    $ sudo systemctl restart sshd

Guide compatibility:

Operating System
Ubuntu Linux
Debian Linux
Red Hat Enterprise Linux
Fedora Linux
CentOS Linux
openSUSE Linux
SUSE Linux Enterprise Server
FreeBSD
OpenBSD
NetBSD
macOS
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