Abstract: A method of operating an Access Node (AN) includes polling a client by periodically causing a query message to be sent to each client that has established a communication link with the AN, and listening for a response message from the client. In one aspect, if the response contains a valid link-local address as the source address of the client, but for which the AN has no record of the Media Access Control (MAC)-Internet Protocol (IP) address-relation, then the AN performs a Duplicate Address Detection (DAD) operation towards the IP network. If no collision is detected enforces the MAC-IP address relation for the link-local address of the client. In another aspect, if the client does not respond, and the AN has a record of an existing removable MAC-IP address-relation for the client, the AN removes that existing removable address-relation.