[DNSOP] DNS terminology: "Passive DNS"

Robert Edmonds <edmonds@mycre.ws> Wed, 18 March 2015 02:56 UTC

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Date: Tue, 17 Mar 2015 22:56:44 -0400
From: Robert Edmonds <edmonds@mycre.ws>
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Subject: [DNSOP] DNS terminology: "Passive DNS"
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Hi,

draft-hoffman-dns-terminology-02 has the following definition:

   Passive DNS -- A mechanism to collect large amounts of DNS data by
   storing queries and responses from many recursive resolvers.  Passive
   DNS databases can be used to answer historical questions about DNS
   zones such as which records were available for them at what times in
   the past.

I think this is referring to the concept originally described in Florian
Weimer's "Passive DNS Replication" paper [0], which sort of combines the
collection and retention aspects into a single term.  Also, scale
("large", "many") may be an interesting property of a particular
deployment, but it isn't really intrinsic to the definition of the term.
Nor do all systems collect both queries and responses (some only collect
responses).  I would propose something like the following instead:

   Passive DNS Replication -- A mechanism to collect and store resource
   records by observing responses, usually those sent by authoritative
   servers. Passive DNS databases can be used to recover DNS records
   which were served in the past, and may allow certain kinds of
   "inverse" searches of the stored records. Sometimes shortened to
   "passive DNS".

[0] http://www.enyo.de/fw/software/dnslogger/first2005-paper.pdf

-- 
Robert Edmonds