nanog mailing list archives

Re: Are public DNS a good thing? (was: Re: 1.1.1.1)


From: Tom Beecher via NANOG <nanog () lists nanog org>
Date: Fri, 18 Jul 2025 11:15:23 -0400


are we talking about BCP-140, aka RFC5358 ("Preventing Use of Recursive
Nameservers in Reflector Attacks") ?

Well, it's both, a BCP and RFC - which statement above wins? ... ;-)


Joking aside, I don't see why this BCP would not be relevant today. If you
run an open recursive DNS in the Internet, this still seems to me a valid
document to consider.



My stance on these (which I think mirrors the IETF's definitions) is that
BCPs are a subset of RFCs, and are guidance , not standards. Which, over
time, the 'current' part of the guidance is relevant to consider.

With respect to BCP-140, sure, it's still generally applicable today. I
didn't mean to imply it wasn't in my response. I was more generally
commenting on the age of document bits, and that wasn't clear. So sorry
about the confusion there.



And yes, I was wondering if the redundancy - or centralization - of the
Internet is something to consider. My personal read on all the comments is
that the N.N.N.N public servers are good backup forwarder solutions but for
the sake of a de-centralized, robust Internet one should implement a better
"Plan A". And don't forget BCP-140 when you implement the plan ;-)


Everyone should be considering the impacts of centralization (not just with
DNS) but a lot of people just don't. This recent CF event is a perfect
example. These companies generally are very good at what they're doing, but
the occasional catastrophic mistake happens. If someone wants to put all
their eggs in one basket, they get to enjoy the pain when it bites them.

On Fri, Jul 18, 2025 at 8:20 AM Marc Binderberger <marc+lists () sniff es>
wrote:


On Thu, 17 Jul 2025 15:03:01 -0400, Tom Beecher via NANOG wrote:

With RFCs, no.
With BCP, the middle letter is generally relevant to the discussion.

are we talking about BCP-140, aka RFC5358 ("Preventing Use of Recursive
Nameservers in Reflector Attacks") ?

Well, it's both, a BCP and RFC - which statement above wins? ... ;-)


Joking aside, I don't see why this BCP would not be relevant today. If you
run an open recursive DNS in the Internet, this still seems to me a valid
document to consider.

But "to consider" does not mean "it's the law". Everyone who is willfully
running into these known problems (by setting up a public DNS, I mean)
simply
has to assign the necessary resources to handle the problems. And I assume
Google, CF & Co do this.

In any case, my original question was not with BCP-140 in mind (but thanks
to
Rubens pointing it out!). I was wondering why one should or should not use
these DNS servers. Thanks for all the comments, I am always surprised how
complex even "basic" things like DNS turn out to be.

And yes, I was wondering if the redundancy - or centralization - of the
Internet is something to consider. My personal read on all the comments is
that the N.N.N.N public servers are good backup forwarder solutions but
for
the sake of a de-centralized, robust Internet one should implement a
better
"Plan A". And don't forget BCP-140 when you implement the plan ;-)

Regards, Marc




On Thu, 17 Jul 2025 15:03:01 -0400, Tom Beecher via NANOG wrote:

RFC 1035 is still what defines DNS, hasn't been obsoleted and is from
1987.
Perhaps age is not the main factor in defining obsolescence ?


With RFCs, no.

With BCP, the middle letter is generally relevant to the discussion.

On Thu, Jul 17, 2025 at 2:40 PM Rubens Kuhl via NANOG
<nanog () lists nanog org>
wrote:

On Thu, Jul 17, 2025 at 1:18 PM Paul Ebersman via NANOG
<nanog () lists nanog org> wrote:

This raises my question: are public DNS like 1.1.1.1 or Google's
8.8.8.8 actually a good thing?

rubensk> According to BCP-140, no, not a good thing.

That BCP is from 2015...

RFC 1035 is still what defines DNS, hasn't been obsoleted and is from
1987.
Perhaps age is not the main factor in defining obsolescence ?


Rubens
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