Hardening SSH (Secure Shell) on your Debian / Ubuntu server is something that should be done immediately. It is not hard to do and can save you from lots of potential brute force attacks. Change the Default SSH Port Changing the default SSH port is one of the easiest...
If you have ever seen your log files, you know the attempts to break into your server seem to never stop. In order to drastically reduce the amount of brute force attacks and other malicious login activity, install Fail2Ban on your Debian / Ubuntu server. Fail2Ban...