An electronic device that generates an interface identifier to determine an IP address to use, the device comprising: an interface identifier generating unit to generate the interface identifier; and a temporary IP address determining unit to determine a temporary IP address containing the interface identifier generated by the interface identifier generating unit and a prefix; characterized by a duplication determining unit to determine whether the temporary IP address determined by the temporary IP address determining unit is the same as an IP address of another electronic device; and an IP address determining unit to specify the temporary IP address as the IP address to use, when it is determinable by the duplication determining unit that the temporary IP address is not the same as the IP address of said another electronic device; wherein the interface identifier generating unit is adapted to generate another interface identifier, when it is determinable by the duplication determining unit that the temporary IP address is the same as the IP address of said another electronic device, and the interface identifier generating unit is adapted to - insert values excluding FFFE between high 24 bits and low 24 bits of a MAC address of the electronic device, or - change a special address range in a MAC address assigned by IEEE to a vendor, or - change values in a range not assigned to hardware in a MAC address assigned by IEEE to a vendor, or - use a hash function as a random number generator function to generate a MAC address. an interface identifier generating unit to generate the interface identifier; and a temporary IP address determining unit to determine a temporary IP address containing the interface identifier generated by the interface identifier generating unit and a prefix; characterized by a duplication determining unit to determine whether the temporary IP address determined by the temporary IP address determining unit is the same as an IP address of another electronic device; and an IP address determining unit to specify the temporary IP address as the IP address to use, when it is determinable by the duplication determining unit that the temporary IP address is not the same as the IP address of said another electronic device; wherein the interface identifier generating unit is adapted to generate another interface identifier, when it is determinable by the duplication determining unit that the temporary IP address is the same as the IP address of said another electronic device, and the interface identifier generating unit is adapted to - insert values excluding FFFE between high 24 bits and low 24 bits of a MAC address of the electronic device, or - change a special address range in a MAC address assigned by IEEE to a vendor, or - change values in a range not assigned to hardware in a MAC address assigned by IEEE to a vendor, or - use a hash function as a random number generator function to generate a MAC address. - insert values excluding FFFE between high 24 bits and low 24 bits of a MAC address of the electronic device, or - change a special address range in a MAC address assigned by IEEE to a vendor, or - change values in a range not assigned to hardware in a MAC address assigned by IEEE to a vendor, or - use a hash function as a random number generator function to generate a MAC address.