This invention makes it possible to automatically install the device driver of only an intended network device on a network. Pieces of identification information for temporarily recognizing partners are input in both a client terminal and a network compliant device corresponding to a driver to be installed. When the identification information is input, the network compliant device multicasts a Hello message which describes the identification information and is necessary to enter the network. The client terminal receives the Hello message, and when information which matches the input identification information is described in the Hello message, shifts to a process based on UPnP. When the client terminal receives a Hello message not containing any description which matches the identification information, it does not notify the OS of the message.