[CentOS] Defending againts simultanious attacks

MrKiwi wrote:
> Oh my ... im not a policeman, but that may have been a freudian slip?
>
> I meant "Port Knocking", and i have no idea what "Pork Knocking" is, 
> although it does sound like an old english sport of the common people?

in a nutshell, your server listens for a special packet on a arbitrary 
port, then allows the source IP of that packet to make a connection on 
another port.    for instance, a UDP packet to port 3515 with a specific 
payload, and you then open up SSH on 22 to the source of that UDP for 
the next 10 seconds or whatever.