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 a large number of invalid entries caused by an unauthorized station sending false replies to the switch's ND queries. 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.