[OpenSIPS-Users] nortpproxy_str usage

Bogdan-Andrei Iancu bogdan at opensips.org
Mon Jan 15 11:08:41 EST 2018

Hi William,

IF you end up chaining multiple RTPproxy'es, you need to be sure you 
avoid the "learning" deadlock between them - as rtpproxy is normally 
waiting to receive RTP in order to learn the end-points IP+port (as the 
IP coordinates from SDP are private, so not usable). So, if the IP in 
the received SDP in public, use the "r" flag when triggering rtpproxy 
(not to wait, but to trust the IP+port in SDP) - see 

Best regards,

Bogdan-Andrei Iancu

OpenSIPS Founder and Developer
OpenSIPS Summit 2018

On 01/12/2018 08:48 PM, William Simon wrote:
> I have a provider that is reflecting the a=nortpproxy:yes attribute 
> back to me in the SDP of its reply. I know it's being reflected back 
> because when I customize that header using the nortpproxy_str setting, 
> I get my own value back in the provider's replies.
> The result is that the answer side of rtpproxy isn't engaged and 
> there's no audio.
> From an old thread 
> (http://lists.opensips.org/pipermail/users/2012-November/023444.html) 
> it seems like the best option for me is to simply disable this 
> a=nortpproxy:yes attribute and let the opensips logic engage rtpproxy 
> all the time.
> What kind of negative side effects would I face by disabling this and 
> letting rtpproxy engage every time? Is this flag only really useful 
> when you are working with a hierarchy of SIP proxies in your own 
> environment? My topology has two equal-priority equal-weight opensips 
> proxies that serve as clustered load balancer as well as 
> outbound-proxy for internal freeswitch servers.
> Thanks
> W Simon
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