Latest Switchfin includes a new option in the menuconfig. Now you can select and compile a simple DHCP server.

If enabled the PBX will be able to assign IP addresses and other config information to the network devices with an active DHCP client.
In most of the cases your local network has already a DHCP server. So what will happen in this case.
The DHCP clients get an IP address/configs by broadcasting a request on the network. All DHCP servers on that physical subnet will reply.
The client will accept the information from the first DHCP server that responds.