Relay

Some network engineers might choose to configure each router to act as the DHCP server for its connected LANs.

However, large enterprises often choose to use a centralized DHCP server.

If the server is centralized, it won't receive the DHCP clients' broadcast DHCP messages. (broadcast messages don't leave the local subnet).

To fix this, you can configure a router to act as a DHCP relay agent.

The router will forward the clients' broadcast DHCP messages to the remote DHCP server as unicast messages.