Duplicate Address Detection (DAD)

DAD verifies that a configured unicast IPv6 address is unique before it is assigned to a VLAN interface on the switch. DAD is enabled in the default IPv6 configuration and can be reconfigured, disabled, or re-enabled at the global config or per-interface command level. DAD can be useful in helping to troubleshoot erroneous replies to DAD requests, or where the neighbor cache contains many invalid entries caused by an unauthorized station sending false replies to the ND queries of the switch. If DAD verifies that a unicast IPv6 address is a duplicate, the address is not used. If the link-local address of the VLAN interface is found to be a duplicate of an address for another device on the interface, the interface stops processing IPv6 traffic.