Duplicate Address Detection

IPv6 Duplicate Address Detection (DAD) is described in RFC 4862. DAD uses neighbor solicitation and neighbor Advertisement messages to verify the uniqueness of an address. DAD must be performed on unicast addresses prior to assigning them to an interface. An address remains in a tentative state while DAD is being performed. If a tentative address is found to be a duplicate, an error message is returned and the address is not assigned to the interface.