A relay apparatus includes: a tag information acquisition section that acquires tag information attached to the network-connected device; a management section that manages the tag information read out by the tag information acquisition section and an IP address assigned by the management apparatus, and an identification information assigned to the relay apparatus itself in association with one another; and a processing section that receives information that the management apparatus has transmitted with the tag information or IP address as a transmission destination and receives information transmitted from the network-connected device for execution of predetermined processing.