A system and method for Internet telephony between a caller station and a callee station are described. The caller station is connected to a first edge network via a first telephony interface, and the callee station is connected to a second edge network via a second telephony interface. An intermediate network is connected to the first edge network via a first router and is connected to the second edge network via a second router. The callee station is associated with a callee station number. The first router initiates the call in response to a setup message that includes the callee station number. A first gatekeeper, controlling the first router, and a second gatekeeper, controlling the second router, together mediate the process of setting up the call. A back end server, in communication with the first and second gatekeepers, stores the addresses and station numbers needed to set up the call. During the call, the first router performs network address translation to transmit signals between the first edge network and the Internet, and the second router performs network address translation to transmit signals between the second edge network and the Internet.