In one embodiment, an aggregation device is configured to aggregate traffic of a plurality of customer edge (CE) devices into a single bridge-domain. The aggregation device receives connectivity fault management (CFM) packets of a CFM protocol from the plurality of CE devices. Each received CFM packet includes a media access control (MAC) address of an access port of the CE device from which the CFM packet was transmitted. The aggregation device detects conflicting MAC addresses between access ports of CE devices by comparing MAC addresses of the received CFM packets. The aggregation device notifies one or more of the plurality of CE devices of the conflict.