[Asterisk-Users] NAT Far End Traversal

[Jean-Michel Hiver]

dbakkerlist at arrayasolutions.com wrote:

>
> The IAX protocol gets around all NATn?

It's much more NAT friendly than SIP.

You know I can't believe that something that such a new, big standard as 
SIP doesn't account for all environments.

Roughly, at the moment, this is the situation *to my knowledge*. If I'm 
wrong correct me...

* H323: absolutely not NAT friendly, few ATAs support it.
* SIP: not very nat friendly. Can be worked around with expensive 
servers. Lots of ATAs support it.
* IAX: very nat friendly. Few ATAs support it. To my knowledge these 
beasts aren't very stable.

What would be cool would be solid SIP ATAs with VPN built in. Since VPN 
would solve the NAT issue altogether.
Also an advantage of VPN is that it works around evil providers which 
filter SIP RTP streams.

Unfortunately, I don't know any...