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.
If you later enable the DHCP server, the DHCP relay will be automatically disabled, and if you enable the DHCPv6 server, the DHCPv6 relay will be disabled. ...
