These would be a great subject. (most people have them but are not aware of the risks)
I'm not sure if there are any tools that can Brute Force checks for ports that open when knocked.

I'm interested in looking at Games Consoles at a stealthy way to gain entry into systems.

That advisory caused Sony to employ Trendmicro to create a very basic type of firewall filter for the PS3

I'm sure the Ps3 has ports which are closed, unless knocked. But I was wondering if anyone had any advice for my ongoing research.

I know this is a BT forum and not a general security forum but everyone here has an interest in Security as well as BT.

PS this is for research purposes on my own machines and not for access generally. Any help will be credited in any white papers etc.