WiFi Calling and response to UDP traffic

[Primitive]

@AndrewZ

I don't think so. This is what ISPs are implementing globally across the network.
Maybe you need to install a package and make some configuration?
See https://openwrt.org/docs/guide-user/network/ipv6_ipv4_transitioning#dual-stack_lite_tunnel_ds-lite_ipv4_in_ipv6

Thank you for this, I will look at it right now!

Those ports are TCP, not UDP.

Actually, they're either. But not really what we're here to discuss.
See: https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

[Primitive]

@AndrewZ

I don't think so. This is what ISPs are implementing globally across the network.
Maybe you need to install a package and make some configuration?
See https://openwrt.org/docs/guide-user/network/ipv6_ipv4_transitioning#dual-stack_lite_tunnel_ds-lite_ipv4_in_ipv6

So I read this, and installed the package, but it appears that to get this working I would need to know my ISP's AFTR... Which I don't... Do you know any way to find this? Also, willing to try it (I'll try almost anything at this point) but I don't think this is going to solve my problem.

[AndrewZ]

I would try to sniff DHCPv6 packets and see if AFTR is there.
See also RFC 6334 - DHCPv6 AFTR Discovery - automatic address resolution in DS-Lite (Ipv6)