Patent ID: 6920136

Claim:
A method for notifying a first apparatus using IPv4 as a communication protocol of an IP address of a second apparatus using IPv6 as a communication protocol, comprising the steps of: receiving a first message requesting an IPv4 address as an IP address of said second apparatus, said first message being sent from said first apparatus; sending a second message inquiring of an IP address of said second apparatus to a manager apparatus which manages address information; when receiving a third message containing an IPv6 address of said second apparatus, said third message being sent from said manager apparatus in response to said second message, performing recognition that the IPv6 address thus received of said second apparatus differs in a protocol version from the IPv4 address requested by said first apparatus; converting the IPv6 address of said second apparatus into an IPv4 address; and sending a fourth message containing the IPv4 address thus converted to said first apparatus as an IP address of said second apparatus, the IPv4 address thus converted having a same protocol version as that of the IP address requested by said first apparatus.