I'm running Asterisk on an external static IP address, siproxd on a different server with its own external static IP address, and communicating using a Grandstream behind a NAT firewall configured to register with Asterisk using siproxd as the outbound proxy. Now I'm aware that siproxd is not intended to be used as an outbound proxy but rather as a SIP relay when installed on the same box as the NAT firewall software (i.e. with access to both the internal and external NICs). With that said, however, things work wonderfully.....but calls outbound from the GS phone are terminated after five seconds of audio. Inbound calls from Asterisk to the GS phone have no problems at all. What am I missing? What config files should I be looking at? And what information does the collective intelligence of this list need to analyse the source of the problem. Thanks for any help you can provide. g.