[dns-operations] root? we don't need no stinkin' root!

Florian Weimer fw at deneb.enyo.de
Wed Nov 27 22:08:23 UTC 2019

* Mark Allman:

> Let me try to get away from what is or is not "big" and ask two
> questions.  (These are legit questions to me.  I have studied the
> DNS a whole bunch, but I do not operate any non-trivial part of the
> DNS and so that viewpoint is valuable to me.)
> (1) Setting aside history and how things have been done and why
>     (which I am happy to stipulate is rational)... At this point,
>     are there tangible benefits for getting information about the
>     TLD nameservers to resolvers as needed via a network service?
> (2) Are there fundamental problems that would arise in recursive
>     resolvers if the information about TLD nameservers was no longer
>     available via a network service, but instead had to come from a
>     file that was snarfed periodically?

What's the change rate for the root zone?  If there is a full
transition of the name server addresses for a zone, how long does it
typically take from the first change to the completion of the sequence
of changes?

If the answer, “this has never happened”, then using a fairly static
data source should probably be okay (similar to how the browser PKI is
maintained).  Due to the way DNSSEC works with its periodic renewal of
signatures, validating non-recursive resolvers will automatically
verify the freshness of the local root zone copy.  Even if there are
few such clients, I expect that for most operators, it will
effectively prevent undetected decay due to a stale root zone (where
more and more stale delegations accumulate until performance is
seriously impacted, and fresh bootstrap using external data is

The other question is whether that data source will make it harder for
ICANN or someone else to hand over control over the TLD in a
unilateral manner.  And then it's not even clear whether that's a good
thing or not.

Other uncertainties relate to the size of the root zone.  It seems
that the phase of aggressive growth is more or less over.  But
hard-coding an assumption that resolvers can load the root zone into
memory is on a different level because it limits policy basically for

I've thought a bit whether the root domain list should be pushed into
(non-validating) stub resolvers, but I don't think that's possible
because people really like to use local domains.

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