I found on: www.informatik.uni-bremen.de/~prelle/terena/cookbook/main/ch04s07.html ----->: When both parties are behind two different NATs, then this approach will not work. The reason is very simple, since both SIP user agents are behind NAT, both of them need to send the first media packet to open pinholes in NAT. Both of them will use the data received in SDP, but that will not work because NATs might have changed the port number. To solve the situation, an intermediary in the public internet will be necessary -- an RTP proxy. The RTP proxy will receive all the media traffic from both parties and send it to the other side. Because it will be located in the public internet it can wait for the first media packet from both sides and send subsequent media packets to IPs and port from which it received the first packets. -----< I've tried with the stun server and without rtpproxy. The SIP signaling was working properly but there was not voice communication between UAs. Grzegorz <"Neill Wilkinson" wrote> Behalf Of Grzegorz _______________________________________________ Serusers mailing list serusers(a)lists.iptel.org http://lists.iptel.org/mailman/listinfo/serusers