Patent ID: 7912048

Claim:
A method of detecting a network address translation device which transfers original network data to a first device, comprising: obtaining an address of a second device connected to a network; generating pseudo network data in which the address is set as a destination address, and in which a number of times that the pseudo network data is able to be transferred is set as a number of transfers required to reach the first device; transmitting the pseudo network data to the second device; detecting a message from the second device, the message indicating that the pseudo network data cannot be further transferred; determining that the second device is operating the network address translation device, in response to a detection of the message, and further in response to a presence of a discontinuity between two successive transmission control protocol (TCP) timestamps of two successive output network data packets transmitted from the second device within a specified time period; and changing the original network data including setting the number of times that the original network data is able to be transferred from an initial time to live value of an operating system to 1 when it has been determined that the second device generates an incorrect checksum based on the network address translation device changing values associated with the pseudo network data.