There has been a lot of buzz lately on security layer when it comes to running services/open ports and how to step away from the security risk line, at least with just one step.
Port Knocking can be summarized in three steps
My service’s port is locked by default
My service’s port will not open unless you send some packets to a sequence of port I selected
My service’s port therefore remains unseen to brute force bots and script kiddies scanners.