Re: [DNSOP] Terminology question: split DNS

Andrew Sullivan <ajs@anvilwalrusden.com> Tue, 20 March 2018 13:52 UTC

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From: Andrew Sullivan <ajs@anvilwalrusden.com>
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Subject: Re: [DNSOP] Terminology question: split DNS
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On Mon, Mar 19, 2018 at 05:58:08PM +0000, Ted Lemon wrote:
>   Where DNS servers that are authoritative for a particular set of domains
>   provide partly or completely different answers in those domains depending
>   on the source of the query.   The effect of this is that a domain name that
>   is notionally globally unique nevertheless has different meanings for
>   different network users.

I mostly like that, but I quibble with "source of the query".  It's
really "depending on some factor apart from the name, class, and type
of the query.  For instance, the answers might differ according to the
source of the query."  EDNS client subnet is another example, but I've
also seen things based on authentication (SIG(0) or TSIG).
Effectively, every "DNS tricks" service on the public Internet is also
a kind of split horizon.

I think we should include all of "split DNS", "split horizon", and
"split brain": they're all terms I've heard and so we ought to make
sure they're both included.

A

-- 
Andrew Sullivan
ajs@anvilwalrusden.com