Section 8: IPv6-mostly networks can provide NAT64 w/o DNS64

[furry13]

(copying from an email I sent to the authors)

With PREF64 being available, some networks might only provide PREF64 and do not use DNS64, as the latter has a number of disadvantages, such as breaking DNSSEC and not working if the host has custom DNS
servers configured.

So do you think it's worth adding some text saying that some Ipv6-only
or, more likely, IPv6-mostly networks might only deploy PREF64 w/o DNS64?

See https://www.ietf.org/archive/id/draft-link-v6ops-6mops-00.html#name-dns-vs-dns64

[tfpauly]

I think we need to clarify that clients need to send an A query in addition to a AAAA query if PREF64 is available, to ensure that the network doesn't need to run DNS64.

[DavidSchinazi]

Maybe we treat this scenario similar to how we handled hostnames with broken AAAA records in HEv2 ? (Try AAAA first and if that doesn't work then try A? Or are we expecting PREF64 without DNS64 to be common and expected?

[tfpauly]

Jen was trying to be able to remove DNS64 in general, since it breaks DNSSEC, etc, etc

[DavidSchinazi]

I see. Maybe we split up the PREF64 and DNS64 algorithms completely then, with the PREF64 algorithm preferred over the DNS64 one