Abstract: A system and method for exchanging online information over a private network. A client with a private Internet protocol (IP) address can exchange a user datagram protocol (UDP) packet with a server with a public IP address according to a real time protocol by first sending information about its IP address to the server such that a router connecting the server to the client maps the sent IP address information to the client. Therefore, the client and server can perform two-way UDP packet communications therebetween. This enables a client with a private IP address to perform two-way voice packet communications with a Voice Over IF (VoIP) provider.