DNS Privacy Considerations
RFC 7626
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Type |
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RFC - Informational
(August 2015; No errata)
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Last updated |
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2015-10-14
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Replaces |
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draft-bortzmeyer-dnsop-dns-privacy
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IETF
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plain text
pdf
html
bibtex
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Reviews |
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WG state
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Submitted to IESG for Publication
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Document shepherd |
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Warren Kumari
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Shepherd write-up |
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Show
(last changed 2015-03-23)
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| IESG |
IESG state |
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RFC 7626 (Informational)
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Consensus Boilerplate |
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Yes
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Telechat date |
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Responsible AD |
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Terry Manderson
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Send notices to |
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(None)
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| IANA |
IANA review state |
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Version Changed - Review Needed
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IANA action state |
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No IC
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Internet Engineering Task Force (IETF) S. Bortzmeyer
Request for Comments: 7626 AFNIC
Category: Informational August 2015
ISSN: 2070-1721
DNS Privacy Considerations
Abstract
This document describes the privacy issues associated with the use of
the DNS by Internet users. It is intended to be an analysis of the
present situation and does not prescribe solutions.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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/rfc7626.
Copyright Notice
Copyright (c) 2015 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 Informational [Page 1]
RFC 7626 DNS Privacy August 2015
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. The Alleged Public Nature of DNS Data . . . . . . . . . . 4
2.2. Data in the DNS Request . . . . . . . . . . . . . . . . . 5
2.3. Cache Snooping . . . . . . . . . . . . . . . . . . . . . 6
2.4. On the Wire . . . . . . . . . . . . . . . . . . . . . . . 7
2.5. In the Servers . . . . . . . . . . . . . . . . . . . . . 8
2.5.1. In the Recursive Resolvers . . . . . . . . . . . . . 8
2.5.2. In the Authoritative Name Servers . . . . . . . . . . 9
2.5.3. Rogue Servers . . . . . . . . . . . . . . . . . . . . 10
2.6. Re-identification and Other Inferences . . . . . . . . . 11
2.7. More Information . . . . . . . . . . . . . . . . . . . . 11
3. Actual "Attacks" . . . . . . . . . . . . . . . . . . . . . . 11
4. Legalities . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Security Considerations . . . . . . . . . . . . . . . . . . . 12
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.1. Normative References . . . . . . . . . . . . . . . . . . 12
6.2. Informative References . . . . . . . . . . . . . . . . . 13
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 17
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction
This document is an analysis of the DNS privacy issues, in the spirit
of Section 8 of [RFC6973].
The Domain Name System is specified in [RFC1034], [RFC1035], and many
later RFCs, which have never been consolidated. It is one of the
most important infrastructure components of the Internet and often
ignored or misunderstood by Internet users (and even by many
professionals). Almost every activity on the Internet starts with a
DNS query (and often several). Its use has many privacy implications
and this is an attempt at a comprehensive and accurate list.
Let us begin with a simplified reminder of how the DNS works. (See
also [DNS-TERMS].) A client, the stub resolver, issues a DNS query
to a server, called the recursive resolver (also called caching
resolver or full resolver or recursive name server). Let's use the
query "What are the AAAA records for www.example.com?" as an example.
AAAA is the QTYPE (Query Type), and www.example.com is the QNAME
(Query Name). (The description that follows assumes a cold cache,
for instance, because the server just started.) The recursive
resolver will first query the root name servers. In most cases, the
root name servers will send a referral. In this example, the
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