I have some users who are IPv6 only, so I got PJSIP working with IPv6, they are able to register and make calls.
However, FreePBX does not seem to be enabling IPv6 for things like the web interface, or most importantly, for LetsEncrypt verification over port 80. The problem is, LetsEncrypt PREFERS IPv6, so it is not even trying to verify over IPv4, the result is that I cannot renew certificates unless I first disable IPv6, then reenable it after manually updating certificates.
I tried to go into settings on FreePBX and add an IPv6 interface in Network Settings. I put in the address as a secondary on Eth0, hit Apply, and it just takes me back to settings and did not appear to do anything at all. No error message either.
When I try and hit FreePBX with HTTP or HTTPS on the IPv6 address, I just get a timeout, no connection. Again, PJSIP works fine.
I have searched and found zero documentation on this.