Patent ID: 8312532

Claim:
A connection supporting apparatus for supporting to establish a Virtual Private Network (VPN) through an Internet Key Exchange (IKE) between a first apparatus and a second apparatus, the connection supporting apparatus comprising: a processor that executes a procedure, the procedure comprising: receiving authentication information of the first apparatus employed in the IKE; judging whether or not a key exchange mode of the first apparatus is a main mode based on the authentication information; judging whether or not an Internet Protocol (IP) address converting apparatus is interposed between the connection supporting apparatus and the first apparatus based on the authentication information and a source IP address of an IP packet when receiving the IP packet containing the authentication information of the first apparatus, transmitting a VPN setting request to the second apparatus when the key exchange mode of the first apparatus is the main mode, the VPN setting request containing the authentication information and a communication key to be used when the first apparatus executes the IKE with respect to the second apparatus; and transmitting both the communication key transmitted to the second apparatus from the connection supporting apparatus and an IP address of the second apparatus to the first apparatus when receiving a response with respect to the VPN setting request from the second apparatus, wherein when the IP address converting apparatus is interposed between the connection supporting apparatus and the first apparatus, the processor executing a procedure for transmitting a VPN setting request which further contains the source IP address of the IP packet to the second apparatus.