The administrative model
DHCPv4–The administrator enables DHCP for each interface. Administration is on a per-logical interface basis.
DHCPv6–Explicit configuration is not necessary. This protocol is enabled on a given physical interface.
DHCPv4–The DHCP server supplies the subnet mask for each address. A hostname option sets the system-wide node name.
DHCPv6–The subnet mask is supplied by Router Advertisements, not the DHCPv6 server. There is no DHCPv6 hostname option.