What a totally cool notion — a firewall security system that’s based on poking and prodding specific ports in a specific order to cause a known response (e.g., opening up a route through the firewall for administrative control). Of course, any one scheme or recipe could never become commonplace enough to be part of a firewall’s default installation; that would degrade its security by making the recipe well-known (which leads to well-hacked).

(Note that this is geeky enough that you can assume I’m posting it mostly as a bookmark for myself. Thanks go to Cory for indulging my geekiness with this.)