Patent ID: 7272846

Claim:
A method for detecting unauthorized access of a cable system by a cable modem, the method comprising: receiving at a cable modem termination system (CMTS), a MAC address proffered by a cable modem seeking to register with the cable system; forming a proffered MAC address/giaddr pair by combining the gateway interface address of the CMTS with the proffered MAC address; comparing components of the proffered MAC address/giaddr pair to the components of each of one or more MAC address/giaddr pairs stored in a datastore; making a determination whether the proffered MAC address/giaddr pair and any of the one or more stored MAC address/giaddr pairs satisfy a matching criteria comprising a same MAC address component and a different gateway interface address component; and in the event the proffered MAC address/giaddr pair and any of the one or more stored MAC address/giaddr pairs satisfy the matching criteria, selecting a remedial response, wherein the remedial response comprises denying the modem registration with the cable system.