A device, a method and a server for performing device identification of electric appliances connected to a network are provided. An information processing device 50, to which electric appliances 20 are communicably connected via a network 2, receives a packet (a response packet or a passive packet) for determining a type of an electric appliance 20, from the electric appliances 20. The information processing device 50 stores definition files defined for each electric appliance 20 in advance, compares the received packet with the definition files for the each electric appliance, scores the packet, extracts a definition file with a high score, and determines electric appliance information of the extracted definition file as electric appliance information of the electric appliance 20.