Short for Inter-AsteriskeXchange, IAX is the native
Asterisk PBX protocol and is now supported by many
VoIP platforms. It has a number of advantages over
SIP including
bandwidth efficiency, it uses a single
UDP port, 4569, so it slides through
NAT with ease, and since it is a binary protocol,
it is more difficult to attack. Despite these advantages IAX is not supported as
widely as SIP, and it also puts a heavier load on your server because all
traffic must pass through the server.
IAX protocol simplifies VoIP After Mark Spencer created Asterisk, the open source PBX, he started to see how this lack of simplicity could be a huge barrier to the VoIP market. In response, he created a new protocol called IAX.
VoIPowering Your Office: Defeat the Pesky NATs of VoIP With IAX If you must support SIP there are a number of ways to get around nasty NAT problems: SIP proxies, STUN (Simple Traversal of UDP through NAT) servers, and majick routers. Or you might consider avoiding SIP entirely and use IAX (Inter-Asterisk Exchange) instead.
