The Dynamic Host Configuration Protocol version 6 (DHCPv6) is a network protocol for configuring Internet Protocol version 6 (IPv6) hosts with IP addresses, IP prefixes, default route, local segment MTU, and other configuration data required to operate in an IPv6 network.
IPv6 hosts that use stateless autoconfiguration may need information other than what SLAAC provides on a given network.
Servers and relay agents listen for DHCP messages on UDP port 547.
[2]: §7.2 The DHCP unique identifier (DUID) is used by a client to get an IP address from a DHCPv6 server.
Four DUID types are identified:[2]: §11 Due to the fact that it is difficult to manage multiple identifiers in a dual-stack environment, and the fact that DUIDs are simply not optimal for some situations, RFC 6939 was released, giving a way to identify a host based on its MAC address.