When it comes to enhancing the Linux server security, there are many ways to do it. Let us take a look to some of the ways here:
1. Restricting or disabling root access.
It is recommended to restrict or disable root access and give it only to the person you trust and to your hosting provider in case of emergency.
Passwords should be reliable and secure - it is a standard to use passwords not shorter than 8 symbols. Also it is advised to use upper- and lowercase letters, numbers and other symbols within one password. Additionally it is advised to change the password more often.
Every time when you transmit data to or from your server it can be intercepted. It is advised to use such instruments as VPN, PGP/GPG keys, SFTP and SSH.
4. Remove unnecessary software.
Remove all services that you don’t need, even working in the background. Also get rid of them in auto start.
5. Apply patches and updates in time and use the latest stable kernel version.