I've just setup a similar configuration as yours.

Could you check the SDP payload of the SIP INVITE that goes from kamailio to the callee ? It should contains the IP address of rtpproxy and the port allocated by the proxy.

Regards,
Pascal

On Thu, Jun 25, 2009 at 12:41 PM, rubenrojas - Trc.es <rubenrojas@trc.es> wrote:
Hello everyone, this is my first post on this list,

I have installed kamailio 1.5.1 and set up a vanilla default kamailio.cfg, then I have modified the cfg to activate mysql, domain, presence, nathelper and authentication with md5, everything works as supposed to, and the clients can register, send txt messages and talk to each other. The only problem is with the audio when the two clients are behind a NAT, the phones can make a call and it does ring too, but when you pick up there is no audio both ways.

when the phones have a public IP everything goes fine, it also works when I use a Linksys PAP2T whith the options to "Insert VIA received", "Insert VIA rport", "Handle VIA received", "Handle VIA rport" and "NAT mapping enable" turned on, with the Qutecom softphone works too. [...]