How To Use Port Knocking to Hide your SSH Daemon from Attackers on Ubuntu
Port knocking is a method of protecting your services behind a firewall until connection attempts are made to a specific sequence of ports in a certain amount of time. The firewall rules are then modified to allow access to the service and the user can connect as normal. In this article, we will discuss how to implement port knocking to add an extra layer of protection to your SSH daemon in order to dissuade attackers.