draft-ietf-dnsop-qname-minimisation-06.txt   draft-ietf-dnsop-qname-minimisation-07.txt 
Domain Name System Operations (dnsop) Working Group S. Bortzmeyer Domain Name System Operations (dnsop) Working Group S. Bortzmeyer
Internet-Draft AFNIC Internet-Draft AFNIC
Intended status: Experimental October 5, 2015 Intended status: Experimental October 12, 2015
Expires: April 7, 2016 Expires: April 14, 2016
DNS query name minimisation to improve privacy DNS query name minimisation to improve privacy
draft-ietf-dnsop-qname-minimisation-06 draft-ietf-dnsop-qname-minimisation-07
Abstract Abstract
This document describes one of the techniques that could be used to This document describes one of the techniques that could be used to
improve DNS privacy (see [RFC7626]), a technique called "QNAME improve DNS privacy, a technique called "QNAME minimisation", where
minimisation", where the DNS resolver no longer sends the full the DNS resolver no longer sends the full original QNAME to the
original QNAME to the upstream name server. upstream name server.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 7, 2016. This Internet-Draft will expire on April 14, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction and background . . . . . . . . . . . . . . . . . 2 1. Introduction and background . . . . . . . . . . . . . . . . . 2
2. QNAME minimisation . . . . . . . . . . . . . . . . . . . . . 2 2. QNAME minimisation . . . . . . . . . . . . . . . . . . . . . 3
3. Possible issues . . . . . . . . . . . . . . . . . . . . . . . 3 3. Possible issues . . . . . . . . . . . . . . . . . . . . . . . 4
4. Protocol and compatibility discussion . . . . . . . . . . . . 5 4. Protocol and compatibility discussion . . . . . . . . . . . . 5
5. Operational considerations . . . . . . . . . . . . . . . . . 5 5. Operational considerations . . . . . . . . . . . . . . . . . 5
6. Performance considerations . . . . . . . . . . . . . . . . . 5 6. Performance considerations . . . . . . . . . . . . . . . . . 5
7. Security considerations . . . . . . . . . . . . . . . . . . . 6 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION 6 8. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7 9. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION 7
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
10.1. Normative References . . . . . . . . . . . . . . . . . . 8 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . 8 11.1. Normative References . . . . . . . . . . . . . . . . . . 8
10.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 9 11.2. Informative References . . . . . . . . . . . . . . . . . 8
11.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Appendix A. An algorithm to find the zone cut . . . . . . . . . 9 Appendix A. An algorithm to find the zone cut . . . . . . . . . 9
Appendix B. Alternatives . . . . . . . . . . . . . . . . . . . . 10 Appendix B. Alternatives . . . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction and background 1. Introduction and background
The problem statement is exposed in [RFC7626]. The terminology The problem statement is exposed in [RFC7626]. The terminology
("QNAME", "resolver", etc) is also defined in this companion ("QNAME", "resolver", etc) is also defined in this companion
document. This specific solution is not intended to fully solve the document. This specific solution is not intended to fully solve the
DNS privacy problem; instead, it should be viewed as one tool amongst DNS privacy problem; instead, it should be viewed as one tool amongst
skipping to change at page 6, line 28 skipping to change at page 6, line 32
.example nameservers a query for .example nameservers a query for
www.host.group.department.example.com and immediately get a specific www.host.group.department.example.com and immediately get a specific
referral or an answer, without the need for more queries to probe for referral or an answer, without the need for more queries to probe for
the zone cut. For such a name, a cold resolver with QNAME the zone cut. For such a name, a cold resolver with QNAME
minimisation will, depending how QNAME minimisation is implemented, minimisation will, depending how QNAME minimisation is implemented,
send more queries, one per label. Once the cache is warm, there will send more queries, one per label. Once the cache is warm, there will
be no difference with a traditional resolver. Actual testing is be no difference with a traditional resolver. Actual testing is
described in [huque-qnamemin]. Such deep domains are specially described in [huque-qnamemin]. Such deep domains are specially
common under ip6.arpa. common under ip6.arpa.
7. Security considerations 7. IANA Considerations
This document has no actions for IANA.
8. Security Considerations
QNAME minimisation's benefits are clear in the case where you want to QNAME minimisation's benefits are clear in the case where you want to
decrease exposure to the authoritative name server. But minimising decrease exposure to the authoritative name server. But minimising
the amount of data sent also, in part, addresses the case of a wire the amount of data sent also, in part, addresses the case of a wire
sniffer as well the case of privacy invasion by the servers. sniffer as well the case of privacy invasion by the servers.
(Encryption is of course a better defense against wire sniffers but, (Encryption is of course a better defense against wire sniffers but,
unlike QNAME minimisation, it changes the protocol and cannot be unlike QNAME minimisation, it changes the protocol and cannot be
deployed unilaterally. Also, the effect of QNAME minimisation on deployed unilaterally. Also, the effect of QNAME minimisation on
wire sniffers depend on whether the sniffer is, on the DNS path.) wire sniffers depend on whether the sniffer is, on the DNS path.)
QNAME minimisation offers zero protection against the recursive QNAME minimisation offers zero protection against the recursive
resolver, which still sees the full request coming from the stub resolver, which still sees the full request coming from the stub
resolver. resolver.
All the alternatives mentioned in Appendix B decrease privacy in the All the alternatives mentioned in Appendix B decrease privacy in the
hope of improving performances. They must not be used if you want hope of improving performances. They must not be used if you want
the maximum privacy. the maximum privacy.
8. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION 9. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION
This section records the status of known implementations of the This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC6982]. Internet-Draft, and is based on a proposal described in [RFC6982].
The description of implementations in this section is intended to The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may features. Readers are advised to note that other implementations may
exist. exist.
skipping to change at page 7, line 24 skipping to change at page 7, line 33
According to [RFC6982], "this will allow reviewers and working groups According to [RFC6982], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature. and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as It is up to the individual working groups to use this information as
they see fit". they see fit".
As of today, no production resolver implements QNAME minimisation but As of today, no production resolver implements QNAME minimisation but
it has been publically announced for the future Knot DNS resolver it has been publically announced for the future Knot DNS resolver
[1]. For Unbound, see ticket 648 [2] and for PowerDNS [3]. [1]. For Unbound, see ticket 648 [2] and for PowerDNS
<https://github.com/PowerDNS/pdns/issues/2311>.
The algorithm to find the zone cuts described in Appendix A is The algorithm to find the zone cuts described in Appendix A is
implemented with QNAME minimisation in the sample code zonecut.go implemented with QNAME minimisation in the sample code zonecut.go
[4]. It is also implemented, for a much longer time, in an option of [3]. It is also implemented, for a much longer time, in an option of
dig, "dig +trace", but without QNAME minimisation. dig, "dig +trace", but without QNAME minimisation.
Another implementation was done by Shumon Huque for testing, and is Another implementation was done by Shumon Huque for testing, and is
described in [huque-qnamemin]. described in [huque-qnamemin].
9. Acknowledgments 10. Acknowledgments
Thanks to Olaf Kolkman for the original idea during a KLM flight from Thanks to Olaf Kolkman for the original idea during a KLM flight from
Amsterdam to Vancouver, although the concept is probably much older Amsterdam to Vancouver, although the concept is probably much older
[5]. Thanks for Shumon Huque and Marek Vavrusa for implementation [4]. Thanks for Shumon Huque and Marek Vavrusa for implementation
and testing. Thanks to Mark Andrews and Francis Dupont for the and testing. Thanks to Mark Andrews and Francis Dupont for the
interesting discussions. Thanks to Brian Dickson, Warren Kumari, interesting discussions. Thanks to Brian Dickson, Warren Kumari,
Evan Hunt and David Conrad for remarks and suggestions. Thanks to Evan Hunt and David Conrad for remarks and suggestions. Thanks to
Mohsen Souissi for proofreading. Thanks to Tony Finch for the zone Mohsen Souissi for proofreading. Thanks to Tony Finch for the zone
cut algorithm in Appendix A and for discussion of the algorithm. cut algorithm in Appendix A and for discussion of the algorithm.
Thanks to Paul Vixie for pointing out that there are practical Thanks to Paul Vixie for pointing out that there are practical
advantages (besides privacy) to QNAME minimisation. Thanks to advantages (besides privacy) to QNAME minimisation. Thanks to
Phillip Hallam-Baker for the fallback on A queries, to deal with Phillip Hallam-Baker for the fallback on A queries, to deal with
broken servers. Thanks to Robert Edmonds for an interesting anti- broken servers. Thanks to Robert Edmonds for an interesting anti-
pattern. pattern.
10. References 11. References
10.1. Normative References 11.1. Normative References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities", [RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<http://www.rfc-editor.org/info/rfc1034>. <http://www.rfc-editor.org/info/rfc1034>.
[RFC1035] Mockapetris, P., "Domain names - implementation and [RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <http://www.rfc-editor.org/info/rfc1035>. November 1987, <http://www.rfc-editor.org/info/rfc1035>.
[RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., [RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
Morris, J., Hansen, M., and R. Smith, "Privacy Morris, J., Hansen, M., and R. Smith, "Privacy
Considerations for Internet Protocols", RFC 6973, DOI Considerations for Internet Protocols", RFC 6973, DOI
10.17487/RFC6973, July 2013, 10.17487/RFC6973, July 2013,
<http://www.rfc-editor.org/info/rfc6973>. <http://www.rfc-editor.org/info/rfc6973>.
[RFC7626] Bortzmeyer, S., "DNS Privacy Considerations", RFC 7626, [RFC7626] Bortzmeyer, S., "DNS Privacy Considerations", RFC 7626,
DOI 10.17487/RFC7626, August 2015, DOI 10.17487/RFC7626, August 2015,
<http://www.rfc-editor.org/info/rfc7626>. <http://www.rfc-editor.org/info/rfc7626>.
10.2. Informative References 11.2. Informative References
[RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS [RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS
Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997, Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997,
<http://www.rfc-editor.org/info/rfc2181>. <http://www.rfc-editor.org/info/rfc2181>.
[RFC6982] Sheffer, Y. and A. Farrel, "Improving Awareness of Running [RFC6982] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", RFC 6982, DOI Code: The Implementation Status Section", RFC 6982, DOI
10.17487/RFC6982, July 2013, 10.17487/RFC6982, July 2013,
<http://www.rfc-editor.org/info/rfc6982>. <http://www.rfc-editor.org/info/rfc6982>.
skipping to change at page 9, line 20 skipping to change at page 9, line 29
[huque-qnamemin] [huque-qnamemin]
Huque, S., "Query name minimization and authoritative Huque, S., "Query name minimization and authoritative
server behavior", May 2015, <https://indico.dns- server behavior", May 2015, <https://indico.dns-
oarc.net/event/21/contribution/9>. oarc.net/event/21/contribution/9>.
[huque-qnamestorify] [huque-qnamestorify]
Huque, S., "Qname Minimization @ DNS-OARC", May 2015, Huque, S., "Qname Minimization @ DNS-OARC", May 2015,
<https://storify.com/shuque/qname-minimization-dns-oarc>. <https://storify.com/shuque/qname-minimization-dns-oarc>.
10.3. URIs 11.3. URIs
[1] https://ripe70.ripe.net/presentations/121-knot-resolver- [1] https://ripe70.ripe.net/presentations/121-knot-resolver-
ripe70.pdf ripe70.pdf
[2] https://www.nlnetlabs.nl/bugs-script/show_bug.cgi?id=648 [2] https://www.nlnetlabs.nl/bugs-script/show_bug.cgi?id=648
[3] https://github.com/PowerDNS/pdns/issues/2311 [3] https://github.com/bortzmeyer/my-IETF-work/blob/master/draft-
[4] https://github.com/bortzmeyer/my-IETF-work/blob/master/draft-
ietf-dnsop-QNAME-minimisation/zonecut.go ietf-dnsop-QNAME-minimisation/zonecut.go
[5] https://lists.dns-oarc.net/pipermail/dns- [4] https://lists.dns-oarc.net/pipermail/dns-
operations/2010-February/005003.html operations/2010-February/005003.html
Appendix A. An algorithm to find the zone cut Appendix A. An algorithm to find the zone cut
Although a validating resolver already has the logic to find the zone Although a validating resolver already has the logic to find the zone
cut, other resolvers may be interested by this algorithm to follow in cut, other resolvers may be interested by this algorithm to follow in
order to locate this cut: order to locate this cut:
(0) If the query can be answered from the cache, do so, otherwise (0) If the query can be answered from the cache, do so, otherwise
iterate as follows: iterate as follows:
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