We have recently installed a Polycom 8000HDX behind a sonic Wall TZ215. We have setup NAT on the FIrewall and on the HDX, as well as opened all ports. However, we are having an issue with most incoming calls connecting, but no audio or video passing and then the call disconnecting. I have done a few packet captures, and we can see the negotiating and ringing, and even RTP packets flowing, but still, no audio or video. I have read that these two devices can be picky working together, so I'm hoping that someone else might have some experience getting them to work together.