Before configuring a firewall interface as a DHCP relay agent, make sure you have configured a Layer 3 Ethernet or Layer 3 VLAN interface and that you assigned the interface to a virtual router and a zone. You want that interface to be able to pass DHCP messages between clients and servers. Each interface can forward messages to a maximum of eight external IPv4 DHCP servers and eight external IPv6 DHCP servers. A client sends a DHCPDISCOVER message to all configured servers, and the firewall relays the DHCPOFFER message of the first server that responds back to the requesting client.