The following config will guide you through the process of enabling SSH root login on Ubuntu 16.04 Xenial Xerus Linux Server or Desktop. This guide assumes that you are in possession of root password and are able to login directly on your system as root user. Use the following guide, if you do not have a root’s user password.
By default the root’s ssh remote shell access is denied by default. Any attempt to remote login as root will result in Permission deniedmessage:
$ ssh root@10.0.0.55’s password: Permission denied, please try again.root@10.0.0.55’s password:
In order to enable root ssh login on Ubuntu 16.04 Xenial Xerus Linux run the following command:
$ sudo sed -i ‘s/prohibit-password/yes/’ /etc/ssh/sshd_config
or manually open sshd configuration file /etc/ssh/sshd_config and change line:
FROM:PermitRootLogin prohibit-passwordTO:PermitRootLogin yes
Once you have made the above configuration change restart ssh daemon:
$ sudo systemctl restart sshd
After you restart sshd daemon you will be able to remotely login as a root user:
$ ssh root@10.0.0.55’s password:
Welcome to Ubuntu 16.04 LTS (GNU/Linux 4.4.0-22-generic x86_64)
* Documentation: https://help.ubuntu.com/
22 packages can be updated.20 updates are security updates.
The programs included with the Ubuntu system are free software;the exact distribution terms for each program are described in theindividual files in /usr/share/doc/*/copyright.
Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted byapplicable law.
Linux Troubleshooting 