Overview

If you're familiar with port knocking, you should know the basics and how this technique basically works. If don't have a clue what I'm talking about, feel free to have a look at the Links section. Most port knocking tools are listening for TCP or UDP packets to arrive on specific ports in a specific order. icmpKNOCK is waiting for ICMP echo requests and checks their payloads. Packets that match given criteria trigger some action, e.g. open/close port(s) etc.

The main advantage of this tool is the fact that this approach works with all standard ping tools, regardless of your operating system.