Especially in larger networks, it is possible that you don't want to run the DHCP server on your system, but instead want to pass on DHCP requests to another server. In this case, you can use the pfSense DHCP relay, which can be found by navigating to Services | DHCP Relay. In order to use DHCP Relay, the DHCP server must be disabled on all interfaces. Note, however, that the DHCPv6 server may still be enabled. The converse is also true: in order to use DHCPv6 Relay, you must disable the DHCPv6 server on all interfaces, but you do not have to disable the DHCP server.

To enable to DHCP relay, refer to the following steps: 

1. To enable the DHCP relay, check the Enable checkbox.
2. There is also an Interface(s) list box where you can select the interfaces on which the DHCP relay will be enabled. If you want the DHCP relay to append the circuit ID (the pfSense interface number) and the agent ID, you should check the Append circuit ID and agent ID to requests checkbox.

3. The Destination server edit box allows you to specify the IP address of the DHCP server. You can specify more than one IP address; you can use the Add and Delete buttons to add/delete entries.