(Waiting for laughter to die down)
It has been > 20 years since IPv6 was standardized in some form and adoption by FreePBX users and associated SIP providers seems extremely low by my casual analysis.
What is my casual analysis?
Users: The FreePBX interface doesn’t even allow configuration of PJSIP IPv6 transport, so unless people are manually configuring it in the .conf files, they’re not using it.
Providers: The providers that are often mentioned around here - Telnyx, Twilio, Voip.ms, VoIP Innovations, CallCentric are some that came to mind - are all lacking IPv6 support.
That said, Asterisk/PJSIP works great over IPv6, and most endpoints support it. Even my elderly Cisco 7965 is dual stack and will do SCCP over IPv6. One brand that I know does not is Obihai. Sangoma, Poly, Yealink are some brands that do.
But why bother? Who cares?
All of the NAT stuff goes away… IPv6 endpoints get globally routable public addresses.
T-Mobile cellular clients work natively (TMo only gives out IPv6 addresses and pushes your IPv4-destined traffic through a NAT64).
“Everyone else is doing it!”… for some reason VoIP lags in adoption of IPv6, but web sites and major ISPs have been on IPv6 for years.
It’s the direction of the future. Or the present, to be honest. FreePBX should support it better, you should try it, and ask your SIP providers to support it too. End PSA.
PS: if you have questions about IPv6 with Asterisk or FreePBX I am glad to try to answer them in this thread.