root is a superuser whereas it has full access to Linux or other Unix-based operating systems. Logging in as the root user via SSH for system administration is a big convenience but comes with big security implication.
A compromised root account will give an attacker full access to your server. This could be caused by bots that would normally brute force root SSH account or leaked password / private key of the root user. It is therefore advised to only allow normal user login to a system via SSH and configure sudo access for the user to perform administrative tasks.
$ ssh firstname.lastname@example.org The authenticity of host 'example.com (192.168.111.146)' can't be established. ECDSA key fingerprint is SHA256:dPiDHZPOKKNaz/RgHHaxkexY7L1h1EFcfa5UJUi2s48. Are you sure you want to continue connecting (yes/no/[fingerprint])? yes Warning: Permanently added 'example.com,192.168.111.146' (ECDSA) to the list of known hosts. email@example.com's password: Permission denied, please try again.
Some systems disable root login by default and some other does not. You can enable or disable root user login to your SSH server by configuring PermitRootLogin directive on SSHd configuration on your SSH server.
Specifies whether root can log in using ssh(1). The argument must be yes, prohibit-password, forced-commands-only, or no. The default is prohibit-password.
Make sure you already have a normal user with SSH and preferably sudo access to the system before preventing root access.
$ sudo vi /etc/ssh/sshd_config [sudo] password for user:
Add the line if it doesn't already exist and remove the # at the beginning of the line if exists.
$ sudo systemctl restart sshd
|Red Hat Enterprise Linux|
|SUSE Linux Enterprise Server|
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