Abstract: Input of an address including a network number and a host number can be facilitated. During data communication, part or all of the network number of a destination IP address is acquired and sequentially stored. When an IP address is to be input, part or all of one network number is selected among those which have been stored based on user designation, and user input of any remaining part of the network number and the host number is received. The part or all of the network number and any remaining part of the network number and the host number are combined to form an input IP address.