[Serusers] Help: I can't hear audio although I receive the RTP packets

Hello all, My problem is one of the most strange problems I have ever found. I am using a SER (v0.8.14) configured to support Nated endpoints. I make a call from a NATed SIP endpoint towards another endpoint which is not NATed (static NAT IP to IP translation). Everything seems to work well, as all the mechanism to solve NAT are triggered and all the packets (SDP part) are correctly translated by the SER. I captured all the SIP packets and the call is correctly established. I can see how the NATed endpoint send and receive RTP packets with no problem (aparently). Even all RTP ports are correct according to the previous negotiation (SDP) between both endpoints. Moreover, the negotiated codecs are fully supported. What is happening is REALLY rare... I CAN'T HEAR ANYTHING AT ALL. All audio is well configured and enable. What's more, as soon as I take out the NAT, I make the same call to the same destination and voila! RTP packets are received and HEARD!!! The voice codecs used for communications are exactly the same as the ones used with NAT. I have checked every single packet and SIP message and everything seems OK... I don't what I can do. Any idea? I have packet captures. Anyone who wants to have a look, please tell me. Thank you very much for your attention. Victor _________________________________________________________________ Moda para esta temporada. Ponte al día de todas las tendencias. http://www.msn.es/Mujer/moda/default.asp