A system and method allowing control of VoIP communications by configuring a Network Address Translator (NAT) is provided. In a first NAT configuration, such a port-restricted NAT, peer-to-peer Voice over Internet Protocol (VoIP) communications are permitted between a VoIP originator and a receiver. In a second NAT configuration, such as a symmetrical NAT, peer-to-peer communications are not possible without further cooperation of the NAT. In this manner, an entity that has control of the NAT, such as an ISP, is able to have a degree of control over traffic using network resources such as bandwidth.