MAC Address Cloning

While typically not an issue for DSL subscribers, many cable operators have their systems set up such that your PC is identified by the MAC address of its network card. Your PC’s MAC address is used to uniquely identify you as a subscriber, and without the correct MAC address, your system may not be allocated an IP address. While this is fine in cases where you intend to keep your cable modem connected to your PC, it introduces issues when you attempt to install a hardware router since its MAC address will be different.

Many broadband routers include a feature to “clone” your MAC address such that your router’s external interface takes on the MAC address of your PC’s network card. When enabled, your service provider sees the “correct” address that they have on file, and you’re typically allocated an IP address without issue. To find your PC’s MAC address, use the ipconfig /all command and then configure it on the MAC address clone (or similar) tab on your router.

Author: Dan DiNicolo

Dan DiNicolo is a freelance author, consultant, trainer, and the managing editor of He is the author of the CCNA Study Guide found on this site, as well as many books including the PC Magazine titles Windows XP Security Solutions and Windows Vista Security Solutions. Click here to contact Dan.