A method, apparatus and computer program product for debugging private Virtual Local Area Networks (VLANs) is provided. In a Connectivity Fault Management (CFM) domain wherein a primary Virtual Local Area Network (VLAN) includes promiscuous ports and wherein a secondary VLAN includes isolated ports, a determination is made at a first network device whether a CFM packet is received on a primary VLAN or a secondary VLAN. When the CFM packet is received on a secondary VLAN, then the CFM packet is responses to on the primary VLAN.