How To disable root access via SSH

If you are planning to deploy openssh on any server, you must secure it from hackers. There are several programs on internet which can launch a brute force attack against your ssh server. The first step to a secure ssh server is to disable root access via ssh. Brute force attackers often try to guess root password using dictionary attack.

1. Open sshd_config file using nano. (You must be root to do this.)

sudo nano /etc/ssh/sshd_config

2. Scroll down the file until you locate

LoginGraceTime 120
 PermitRootLogin yes
 StrictModes yes

3. Modify PermitRootLogin to

PermitRootLogin no

4. Save the file by pressing Ctrl-O and exit nano by pressing Ctrl-X.
5. Restart SSH with by entering the command below.

sudo /etc/init.d/ssh restart

After restarting SSH, try to connect using the root account. Access will be denied. However , if you want to access root from a remote machine via ssh, login using a normal user account and use su to become root.

Tags: bash cli disable linux openssh root shell ssh ubuntu