AT&T WiFi calling on iOS drops outbound audio

[jeremygaither]

On 20.7 (and perhaps prior release) I am unable to reliably use AT&T WiFi calling on iOS. I've attempted to set up static NAT rules for ports 500/4500, but outbound audio drops after a few seconds regardless of settings used. I'm also on AT&T uverse/fiber behind their residential gateway, but OPNsense has the public IP address.

Does anyone have AT&T WiFi calling working behind OPNsense, especially if they're also on AT&T u-verse or fiber? Can someone explain how one gets this working?

[RFGuy_KCCO]

I'm on 20.7 and using Wi-Fi Calling on AT&T with an iPhone XS Max and it is working great, with no issues and no special rules set up at all. However, I am using Comcast for internet, not AT&T.

[jeremygaither]

I am also having problems with Zoom dropping my outbound audio. I'm starting to suspect some UDP session or NAT mapping problems are causing both issues. Did NAT mapping change in a big way in this newest release?