Systems and methods for forwarding data packets to facilitate an IP telephony communication make use of a media relay to accomplish the forwarding actions. The media relay is configured receive setup signaling indicating a first acceptable originating IP address for received data packets. The media relay also allows the acceptable originating IP address to change once after the initial call setup has occurred. Also, if a REINVITE action occurs during a call, the media relay will allow the acceptable originating IP address to change once after the REINVITE signaling has been completed.