67 is used to receive the response of the lower-level customer's request to allocate IP 68 or send the request to the customer successfully or failed.

DHCP (Dynamic Host Configuration Protocol) is a local area network protocol, which works with UDP protocol. It has two main purposes: automatically assigning IP addresses to internal networks or network service providers, and providing users or internal network administrators with the means to centrally manage all computers. It is described in detail in RFC 2 13 1. DHCP has three ports, of which UDP67 and UDP68 are normal DHCP service ports, serving as DHCP server and DHCP client respectively. Port 546 is used for DHCPv6 clients, but not for DHCPv4. It is used for DHCP failover, which is a service that needs to be started specially. DHCP failover is used for "hot standby".