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.