[Users] UA behind NAT puts public IP in Contact, Via - help

[Bogdan-Andrei Iancu]

Hi

Arek Bekiersz wrote:

> Hi,
>
>
>
> Few days ago I presented UA that sends public IP in "Contact" and "Via"
> HF, when it is behind NAT. It is in private LAN but it learns its public
> IP and every SIP request will contain public addresses.

they may happen because the phone is using STUN or because of a 
SIP-aware router (on NAT border)

>
> It ruins NAT traversal effort, inluding nathelper + rtpproxy. I cannot
> properly detect NAT-ed user neither by "Via" nor "Contact" check. As a
> result people with various modems get angry and are reporting to me all
> those "I have no audio" problems. Or they cannot even register at all,
> if they have partcularly stupid NAT.

take a look at:
    http://openser.org/docs/modules/1.0.x/nathelper.html#AEN349
you have 5 tests to detect NATed clients

>
> What is your advice?
>
use combined nat detection tests in order to force rtpproxy.

> Vendor knows about issue but doesn't see problem.
> Of course I can enable NAT traversal by "User-Agent" HF check, but 90%
> of those UAs are NOT behind NAT...
>
regards,
bogdan