DNS Query Name Minimisation to Improve Privacy
RFC 7816

Document Type RFC - Experimental (March 2016; Errata)
Last updated 2016-03-24
Replaces draft-bortzmeyer-dns-qname-minimisation
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IESG IESG state RFC 7816 (Experimental)
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IANA IANA review state Version Changed - Review Needed
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Internet Engineering Task Force (IETF)                     S. Bortzmeyer
Request for Comments: 7816                                         AFNIC
Category: Experimental                                        March 2016
ISSN: 2070-1721

             DNS Query Name Minimisation to Improve Privacy

Abstract

   This document describes a technique to improve DNS privacy, a
   technique called "QNAME minimisation", where the DNS resolver no
   longer sends the full original QNAME to the upstream name server.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  This document is a product of the Internet Engineering
   Task Force (IETF).  It represents the consensus of the IETF
   community.  It has received public review and has been approved for
   publication by the Internet Engineering Steering Group (IESG).  Not
   all documents approved by the IESG are a candidate for any level of
   Internet Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7816.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Bortzmeyer                    Experimental                      [Page 1]
RFC 7816                   QNAME Minimisation                 March 2016

Table of Contents

   1. Introduction and Background .....................................2
   2. QNAME Minimisation ..............................................3
   3. Possible Issues .................................................4
   4. Protocol and Compatibility Discussion ...........................5
   5. Operational Considerations ......................................5
   6. Performance Considerations ......................................6
   7. On the Experimentation ..........................................6
   8. Security Considerations .........................................7
   9. References ......................................................7
      9.1. Normative References .......................................7
      9.2. Informative References .....................................8
   Appendix A. An Algorithm to Perform QNAME Minimisation .............9
   Appendix B. Alternatives  .........................................10
   Acknowledgments ...................................................11
   Author's Address ..................................................11

1.  Introduction and Background

   The problem statement is described in [RFC7626].  The terminology
   ("QNAME", "resolver", etc.) is also defined in this companion
   document.  This specific solution is not intended to fully solve
   the DNS privacy problem; instead, it should be viewed as one tool
   amongst many.

   QNAME minimisation follows the principle explained in Section 6.1 of
   [RFC6973]: the less data you send out, the fewer privacy problems
   you have.

   Currently, when a resolver receives the query "What is the AAAA
   record for www.example.com?", it sends to the root (assuming a cold
   resolver, whose cache is empty) the very same question.  Sending the
   full QNAME to the authoritative name server is a tradition, not a
   protocol requirement.  In a conversation with the author in
   January 2015, Paul Mockapetris explained that this tradition comes
   from a desire to optimise the number of requests, when the same
   name server is authoritative for many zones in a given name
   (something that was more common in the old days, where the same
   name servers served .com and the root) or when the same name server
   is both recursive and authoritative (something that is strongly
   discouraged now).  Whatever the merits of this choice at this time,
   the DNS is quite different now.

Bortzmeyer                    Experimental                      [Page 2]
RFC 7816                   QNAME Minimisation                 March 2016
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