[Full-disclosure] Interesting idea for a covert channel or I justdidn't research enough?

[Aditya Deshmukh]

> 
> I myself use this method to open up the SSH port for a particular IP
> address. When you try to open a particular URL on my website, 
> you get a 404
> because that document doesn't exist. The webserver logs this. 
> A script in
> the background sees in the log that this happened, and opens 
> up port 22 to
> the IP address which requested the non-existant URL.

Aren't these all different versions of portknocking ? All of 
them work untill someone outside can figure out the pattern of 
events - at most I would call this security by obscurity - 
Trivial to detect but good enough for some low security 
requirements