If the SIP UA is not behind the NAT, and Kamailio insersts a=nortpproxy:yes in SDP body, can it cause one sided audio.

 

I am using PJSIP as my UA, kamailio 3.1.5 , rtp proxy 1.2.1 as intermediate proxy for signalling and media. In kamailio config, I have enabled WITH_NAT.

On call setup, only one way audio is there. When I looked at SIP messages, the only additional stuff I can see a=nortpproxy and nat=yes in recpord route.

 

Without kamailio as intermediate proxy, audio is good both way.

 

So I feel, when I bring up kamailio as intermediate proxy I am doing some mistake configuration wise either at PJSIP UA or in Kamailio.

 

Has anybody faced this issue previously.

If so please share how can we fix this issue.

 

Thanks in advance

Austin