After a host has generated an IPv6 address using the DHCPv6 or SLAAC (Stateless Address Autoconfiguration) process, the host verifies that the address is unique by performing Duplicate Address Detection (DAD). This involves the host sending an ICMPv6 Neighbor Solicitation message to the newly generated IPv6 address. If no Neighbor Advertisement is returned in response, the host concludes that the address is unique and therefore safe to use. This process ensures that no other device on the local network segment is using the same IPv6 address before the host configures it on its interface.