DHCP servers may coordinate their IP and hostname assignments with a DNS server. This permits dynamic assignment of IP addresses without interfering with access to DHCP Clients by other systems. The other systems utilize the agreed hostname (which DHCP can manage and provide to the client) and obtain the current IP address by means of DNS lookup.
A DHCP Server is in compliance with this optional part of the Basic Network Address Management Profile profile if it maintains and updates the relevant DNS server so as to maintain the proper hostname/IP relationships in the DNS database.
Figure F.1-7 DDNS Coordination
Actor: DHCP Server
Role: Responded to DHCP acquisition queries and assigned IP address to client.
Actor: DNS Server
Role: Maintains the DNS services for the network.
RFC-2136 Dynamic Updates in the Domain Name System
After the DHCP server has assigned an IP address to a DHCP client, the DHCP server uses DDNS to inform the DNS server that the hostname assigned to the DHCP client has been given the assigned IP address. The DNS Server updates the DNS database so that subsequent DNS queries for this hostname are given the assigned IP address. When the lease for the IP address expires without renewal, the DHCP server informs the DNS server that the IP address and hostname are no longer valid. The DNS server removes them from the DNS database.