Originally Posted by rdhw

Surely this is wrong. It makes no sense to clone the STB's own internal MAC address into the router's WAN port. Having two identical MAC addresses on the same network segment will cause all sorts of bad problems.

What sometimes helps is to clone the MAC address of a previously registered customer device into the router's WAN port. In this case, the previously registered customer device is the ethernet-to-USB converter attached to the customer's PC. The MAC address of this can be discovered by opening a command prompt window and typing the command:

ipconfig /all

in the output of which it is listed as "Physical address".