Communication relay device and communication relay method

A communication relay device receives a packet transmitted from a first communication device to a second communication device and forwards the packet to a correspondent communication relay device. The communication relay device includes: a processor and a communication processor. The processor extracts, from a request packet that requests a connection to the second communication device, a first identifier for indicating the first communication device, when the communication relay device receives the request packet from the first communication device, and generates configuration information including the first identifier. The communication processor transmits the configuration information to the correspondent communication relay device such that the correspondent communication relay device converts source information of the packet transmitted from the first communication device to the second communication device into the first identifier and forwards the packet for which the source information has been converted to the second communication device.