Enabling media (audio/video) scenarios across firewalls typically requires opening up multiple UDP ports in an external firewall. This is so because RTP (Real Time Protocol, RFC 1889), which is the protocol used to carry media packets over IP network, requires a separate UDP receive port for each media source. Opening up multiple media ports on the external firewall is something that administrators are not comfortable doing as they consider it security vulnerability. The system and method according to the invention provides an alternate mechanism which changes RTP protocol a little and achieves a goal of traversing firewalls for media packets using a fixed number, namely two, of UDP ports.