You should never allow anyone to ssh directly into your server as root as this could be a serious security risk should anyone be able to brute force your password. Instead, you should disable root ssh access which will force people to login as a normal user and then switch to root.
Here are some tips on securing SSH on your server. This is not everything you need to do but it is a good place to start.
Disabling Root Access
Disabling root access is surprisingly easy. First login to your server as root or a normal user and then su to root.
Second, edit your sshd_config file. Note that there is also a ssh_config file which you don’t need to edit in this tutorial.
Thirdly, find the section with the line shown below, uncomment it if it isn’t already and change the yes to a no.
And lastly, save the file and restart sshd.
After you have completed the above, no one will be able to login as a root user but instead have to switch to root after logging in as a root user.
Additional changes to further secure SSH
Disable X11Forwarding unless of course, you absolutely need to use it. To do this, edit the sshd_config as shown above and find the line as shown below and change it to NO.
Change the SSH protocol from version 1 to the more secure version 2. To do this, edit the sshd_config as shown above and find the line as shown below and change it to 2 instead of 2, 1.
If anyone has any further information, I will be happy hear about it so email me or post a comment below.