Provided is a network system for relaying communication between devices communicating with the Internet using different communication networks. The network system includes a first home network controller which controls first home network devices within a household; a repeater that is connected to the Internet via a first communication network and which relays communication between the Internet and the first home network controller; a second home network controller that is connected to the Internet via a second communication network and which relays communication between the Internet and each of second home network devices within the household; and a management server that is connected to the Internet and relays communication between the first and second home network devices within the household, wherein the first and second home network devices communicate using the first and second communication networks, respectively.