SMC Networks Barricade SMC7908VoWBRA2 - Manual (Page 65)

A
DVANCED
S
ETUP
4-29
Clone MAC Address
Some ISPs require you to register your MAC address with them. If this is
the case, and you have previously registered the MAC address of another
device, the MAC address of the Barricade must be changed to the MAC
address that you have registered with your ISP.