DHCP on a Multi-Segment Network
Subject:   Forwarding of DHCP broadcast in routers
Date:   2003-05-20 11:24:00
From:   anonymous2
An enterprise with several subnets wil usually have a layer 3 switch or router forwarding packets between subnets. That switch or router can forward the DHCP broadcast from the client to the central DHCP server(s) as unicast, much like the DHCP relay servers.

On Cisco boxes you can enable this with "ip helper X.X.X.X" on the relevant interfaces.

Nice and informative article.

- Oyvind