First login to the ubuntu server via terminal or console
To gain super user access, enter the following command and re-type the user password.
sudo su –
Type the following command to set the password for the Root user
passwd root
This will prompt user to enter the new password.
and confirm password
The terminal will return with Password updated successfully!
Simply adding a password for root is not enough for Ubuntu 14.04+ Server.
You need to edit /etc/ssh/sshd_config, and commend out the below line:
PermitRootLogin without-password
Add the following line:
PermitRootLogin yes
Then restart SSH:
service ssh restart
Yes you are done…
login using root account
