A system for stealthy authentication across closed ports, communication in which information arrives encoded in the form of connection attempts to closed ports.
a circle of cells with windows facing inwards, towards a tower, wherein jailers could look out and inspect the prisoners at any time, unseen by their subjects.
(Mostly HP JetDirects, but a little info on the Ricoh Savins), This article will attempt to point out some of the more interesting things that can be done with a network based printer to make it reveal information about its users, owners and the network i