your core needs to be the DHCP server so it can offer plug-and-play and network boot services.we normally put two network cards in the core, one of which is used for the Internet, and the other for the internal home network, and that way and novice homeowner doesn't need to worry about disabling the DHCP server in his existing DSL/cable modem. If you have only one network card, you'll need to disable DHCP in your other device, and in Pluto admin choose advanced, network settings, and give the Pluto core and a static IP address for the Internet, and that also have its default 192.168.80.1, used for the internal network