An access control system for use with a networked computer system [10] comprises a host [14] of the networked computer system, and a bit stream whereby information is transferred from a source of said bit stream to said host [14], said bit stream bearing a routing label identifying an origin of said bit stream in the computer network. The system further comprises a word integrated with said bit stream, said word including a routing label identifying an origin of said word in the computer network, and an access control module in communication with said host, said access control module operable to make an identification, wherein the identification includes comparing the origin of said bit stream to the origin of said word.