[SR-Users] Cannot hear voice with symmetric NAT and STUN

[Daniel-Constantin Mierla]

Hello,

stun works pretty well for non-symmetric nat. If there is symmetric nat, 
then you need a rtp relay (e.g., rtpproxy) or turn server.

Cheers,
Daniel

On 2/28/13 5:48 PM, Khoa Pham wrote:
> Hi David, I already read all of these. But the problem seems 
> contradict with what I read
>
>
> On Thu, Feb 28, 2013 at 9:56 PM, David <kamailio.org at spam.lublink.net 
> <mailto:kamailio.org at spam.lublink.net>> wrote:
>
>     Hello,
>
>     Look on Wikipedia and read the articles for SIP, RTP, NAT and STUN.
>
>     The answer to your question can be found in the above articles.
>
>     David
>
>
>     On 13-02-27 10:26 PM, Khoa Pham wrote:
>>     Hi, I have Kamailio as SIP server and RTP server. Client is PJSIP.
>>
>>     I read that STUN is for non-symmetric NAT, and RTP server is for
>>     symmetric NAT.
>>
>>     Supposed A calls B.
>>
>>     If A, B both use symmetric NAT and STUN, they cannot hear each other
>>     If A or B use non-symmetric NAT and NOT using STUN, they cannot
>>     hear each other.
>>
>>     Why is that?
>>
>>     I read
>>     http://tools.ietf.org/id/draft-takeda-symmetric-nat-traversal-00.txt for
>>     Prediction Failure, is that related to this problem ?
>>
>>     -- 
>>     Khoa Pham
>>     HCMC University of Science
>>     Faculty of Information Technology
>>
>>
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>
>
>     _______________________________________________
>     SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing
>     list
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>
>
>
>
> -- 
> Khoa Pham
> HCMC University of Science
> Faculty of Information Technology
>
>
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-- 
Daniel-Constantin Mierla - http://www.asipto.com
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
Kamailio World Conference, April 16-17, 2013, Berlin
  - http://conference.kamailio.com -

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