Subnets and relays
Because DHCP communications are initiated using broadcasts, they are normally confined to a single subnet. To accommodate DHCP clients and servers separated by one or more routers, a DHCP relay system can be established on subnets without DHCP servers. A relay system listens for DHCP client broadcasts, forwards them to a DHCP server on another subnet, and returns DHCP traffic back to the client. This configuration can centralize DHCP management in a large routed environment.