Patent ID: 7508818

Claim:
An IP telephony method for causing a telephone conversation to take place between a caller's IP telephone terminal and a conversation partner's IP telephone terminal through a proxy and a router using an IP packet including a voice packet, the method comprising: a first record generation step of generating a first record that represents a correspondence between a local IP address of a caller's first IP telephone terminal and a global IP address of the conversation partner's IP telephone terminal; a step of causing the proxy to receive the IP packet transmitted from the caller's first IP telephone terminal; a step of causing the proxy to change a destination IP address of the IP packet to the global IP address of the conversation partner's IP telephone terminal by referring to the local IP address of the caller's first IP telephone terminal and the first record; a first transfer step of causing the proxy to transfer the IP packet, the destination address of which is changed, to the router; and a second transfer step of causing the router to transfer the IP packet, which is received from the proxy, to the conversation partner's IP telephone terminal.