The IAX protocol is a result of the Asterisk community needing to utilize a single UDP for ease of use rather than the issues observed with SIP and NAT-Traversal. The Asterisk VOIP PBX uses this protocol as an alternative to SIP and H.323
• IAX is not the result of a standards group, rather a collaborative, community based effort
• IAX uses a single UDP port 4569, and thus works well in NAT environments. IAX only uses UDP ports within its signaling and Meadia streaming.
IAX
