Hi I have managed to set up our Asterisk server and can successfully make and receive calls via an external Asterisk server service provider and our IAX.conf file. I can make SIP to SIP calls to a remote machine on a fixed IP. I cannot make SIP to SIP calls from one internal phone behind our NAT firewall to another internal phone behind our NAT firewall. The call is received and the recipient can answer it, but no voice nor echo can be heard. Any ideas would be greatly appreciated. Regards James -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.digium.com/pipermail/asterisk-users/attachments/20040713/25d6c667/attachment.htm