[DNSOP] Hybird Resolver/ DNS invariants

[Davey Song <[e-mail]>]

Hi folks,

I happened to run into a discussion of behaviors of  Hybrid Resolver/ DNS
invariants where some of the non-typical uses of DNS are listed, especially
on the resolver. I'm encouraged to put them down as a requirement draft of
these uses of DNS and ask the mailing list whether it is a good idea. I
hope it is helpful to provide information including risk for people who are
doing or going to the same thing.

There are some existing cases in the discussion:
1. A resolver syncs (pull or receive server push) with an authoritative
server. It reduces the recursion and resolves the very-short TTL
requirement. RFC7706 provides an approach. Other resolveless approaches are
used as well..
2. A resolver can forward queries to another resolver if the load is high
to reduce the recursion.
3. A resolver/authoritative server mode serving Apps via DoH or other
Application-level DNS.  Operators of apps can edit each response on demand
and propagate the changes of DNS RR in seconds. It also provides a private
zone and names for each Apps.
4. A Hybrid DNS which is used  as a name server but cache and pull the
authoritative data from another authoritative server. It provides an
approach to easily scale the system without any change of existing
authoritative DNS.

Do you think it is a useful effort for DNSOP WG? Any suggestions or
observed related discussions on the DNS invariants?

Best regards,
Davey