Patent ID: 8131863

Claim:
An address translator to be coupled to a first network utilizing a global address, and to be coupled to a second network utilizing a private address, said address translator comprising: an address translating unit which translates, in a Layer 3 region of communication data the global address into the private address, or translates, in a Layer 3 region of communication data, the private address into the global address; a detecting unit which detects that the communication data conforms to a particular protocol based on a port number contained in a header corresponding to a Layer 4 region of the communication data; a creating unit which creates translation information including a correspondence relationship between the global address and the private address for translating a Layer 3 address contained in a region of the communication data higher than the Layer 3 region, when the detecting unit detects that the communication data conforms to the particular protocol, and a communicating unit which communicates with a server device, and wherein said address translator sends said translation information and the region of the communication data higher than the Layer 3 region to said server device, and receives information including said Layer 3 address described in the region of the communication data higher than the Layer 3 region which has been translated by said server device, wherein said region of the communication data higher than the Layer 3 region comprises a parameter which requires translation of the region of the communication data higher than the Layer 3 region, wherein said address translator sends to said region of the communication data higher than the Layer 3 region with a tag added to said parameter by said address translator, and wherein said server device extracts the parameter which requires the translation from the region of the communication data higher than the Layer 3 region based on said tag which requires the translation of the region of the communication data higher than the Layer 3 region.