Let face it, the Secure Shell (SSH) daemon running on your VPS is the most sensitive service open to attack on your system. Any hacker worth their salt will first try to gain access to your VPS via SSH and 99.9% of all VPS connected to the internet run this service by default and on their public IP.
If somebody gains access to your VPS via the SSH service, you can kiss your data and entire VPS goodbye. This is the ultimate goal for any would-be hacker and as such, needs to be the first thing you secure as a VPS administrator.
In this article I’m going to show you how to take three simple precautions with the SSH service that will stop most hackers and script kiddies in their tracks.
Full article here:
How to Really Secure Your Linux VPS SSH Service (Linuxaria)
Note that while the article and title makes reference to a Virtual Private Server (VPN), there is no reason these techniques would not work with any version of Linux that offers SSH access.