Network Working Group G. Huston
Internet-Draft APNIC
Intended status: Informational P. Koch
Expires: November 25, 2016 DENIC eG
A. Durand
ICANN
W. Kumari
Google
May 24, 2016
Problem Statement for the Reservation of Top-Level Domains in the
Special-Use Domain Names Registry
draft-adpkja-dnsop-special-names-problem-03
Abstract
The dominant protocol for name resolution on the Internet is the
Domain Name System (DNS). However, other protocols exist that are
fundamentally different from the DNS, and may or may not share the
same namespace.
When an end-user triggers resolution of a name on a system that
supports multiple, different protocols (or resolution mechanisms), it
is desirable that the protocol used is unambiguous, and that requests
intended for one protocol are not inadvertently answered using
another.
RFC 6761 introduced a framework by which a particular domain name
could be acknowledged as being special. Various challenges have
become apparent with this application of the guidance provided in RFC
6761. This document aims to document those challenges in the form of
a problem statement in order to facilitate further discussion of
potential solutions.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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time. It is inappropriate to use Internet-Drafts as reference
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This Internet-Draft will expire on November 25, 2016.
Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction: DNS, Name space or Name Spaces, Name Resolution
Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. IETF RFC6761 Special Names . . . . . . . . . . . . . . . . . 3
3. Issues with 6761 . . . . . . . . . . . . . . . . . . . . . . 4
4. Candidate string evaluation and relationship with ICANN . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 7
Appendix A. Editorial Notes . . . . . . . . . . . . . . . . . . 7
A.1. Venue . . . . . . . . . . . . . . . . . . . . . . . . . . 7
A.2. Change History . . . . . . . . . . . . . . . . . . . . . 7
A.2.1. draft-adpkja-special-names-problem-00 . . . . . . . . 7
Appendix B. Change history . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction: DNS, Name space or Name Spaces, Name Resolution
Protocols
For a very long time, DNS and the name space have been perceived as
one and the same. However, this has not always been the case; in the
past, other name resolution protocols were popular. One can remember
NIS, NIS+, host files, UUCP addresses... Most of those have been
obsoleted by the DNS in the late 1990s. More information on the
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history of names and namespaces can be found in
[I-D.lewis-domain-names].
More recently, new name resolution protocols have been proposed, each
addressing a particular need or a particular community. For example,
the DONA handle system has been used by the publication industry.
The Apple "Bonjour" set of protocols, inspired by what was available
on Appletalk networks, has been developed to perform automatic name
resolution on a local IP network. The TOR project is using the onion
system to obfuscate communications, the GNU Name System (GNS) system
is using block chains to build a decentralized name system to offer
"privacy and censorship resistance". Many more have been proposed.
Those alternate name resolution protocols do not exist in a vacuum.
Application developers have expressed a strong desire to build their
software so it will function in any of those universes with minimal
changes. Doing so means that the software has to recognize
deterministically what kind of name it is dealing with and associate
it with the corresponding name resolution protocol. Because of this
desired lack of explicit signaling, an algorithmic solution
frequently chosen by application developers consists simply to use a
special tag padded at the end of a name to indicate an alternate name
resolution method. Examples: if a name ends in .local, the software
uses the Apple Bonjour protocol based on multicast DNS; if the name
ends in .onion, it uses the TOR protocol; if the name ends in .gnu,
it uses the GNS protocol, etc... One noteworthy exception to this
approach is the DONA system that exists independently and has
developed its own interoperability solution with the DNS.
A result of the above is that a number of applications have been
developed (and massively distributed) that have encoded their
favorite "tag" as a DNS TLD in a free-for-all, beginning their
existence squatting on that DNS space... .local, .gnu, .onion
started out like that.
2. IETF RFC6761 Special Names
The IETF used a provision from the IETF/ICANN MoU [RFC2860] section
4.3 that says that "(a) assignments of domain names for technical
uses" is to be considered the purview of IETF (as in, outside of the
scope of ICANN) in order to create a way to reserve such names in a
list of "special names". That process is documented in [RFC6761]
(which curiously does not directly refer the IETF/ICANN MoU). It was
first applied for .local and more recently for .onion. When that
process was put in place, it was thought it would only be used a
handful of times. However, a large number of applications have since
been made to the IETF. The .onion evaluation took almost a year and
has started a massive (and often heated) discussion in the IETF.
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This [RFC6761] process to reserve special name has a number of
issues, that can be grouped in two categories:
o Issues with [RFC6761] itself, including issues discovered during
the evaluation of .onion
o Higher level issues regarding candidate string evaluation and
relationship with ICANN
3. Issues with 6761
1. It can be use to reserve any names, not just TLDs. For example,
it could potentially be used to forbid a registrar to register
specific names in any TLD.
2. [RFC6761] does not mention if the protocol for which it is
requested to reserve a string should be published as an RFC
document. Most applications have, so far, come from outside
organizations, and the described protocols that have not been
developed by the IETF.
3. [RFC6761] does not provide clear enough direction as to what
party is responsible for carrying out the evaluation.
4. There are ambiguities and no formal criteria on how the IETF can
(or even whether the IETF should) evaluate the merits of
applicants to [RFC6761] reservations. Section 5 of [RFC6761]
describes seven questions to be answered by an applicant for
[RFC6761] status. However, running this process for the .onion
application showed that those seven questions are inadequate for
making the determination for whether a particular strings
qualifies as requiring special/different treatment.
5. Placing a string in the [RFC6761] registry does not guarantee
that DNS queries for names within a reserved domain will not be
sent over the Internet. As such, the applicant for [RFC6761]
status cannot be guaranteed that leakage will not occur and will
need to take this into account in the protocol design. Useful
reservations of top-level domains should be accompanied by
documentation of realistic expectations of each of the seven
audiences, and the evaluation of particular requests should
consider the practical likelihood of those expectations being met
and the implications if they are not.
6. The [RFC6761] registry lists the reserved names but does not
include direct guidance, neither in free text form nor in machine
readable instructions, for any of the seven audiences, relying
instead upon a reference for each entry in the Registry to the
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document that requested its insertion. Such documents might well
be opaque to many readers; [RFC6762] is a seventy-page protocol
specification, for example, which is arguably not the most
effective way to set expectations of non-technical end-users
4. Candidate string evaluation and relationship with ICANN
1. IETF does not have process to evaluate the proposed strings
candidate to [RFC6761] status for things like trademark, IPR,
name collision, etc.. Instead, the IETF relies on document
reviews, working group and IETF-wide last call, and ultimately a
decision is made by the IESG. That decision can be appealed,
first to the IAB and second to the ISOC board of trusties.
2. The IETF "review" process is not foolproof. [RFC7788] describing
the "home networking control protocol" was recently published.
That document includes text instructing devices to use names
terminating by default with the .home suffix. [RFC7788] did not
reference [RFC6761] anywhere and had no IANA sections about this
reservation. It was published without anyone noticing this
during the entire review process. The issue was caught after the
publication, and an errata was published.
3. There exists now at least 2 streams to take strings out of the
global namespace: IETF RFC6761 "special names" and ICANN "gTLD
program" (see [NEW-GTLD]). It is important to observed that the
IETF RFC6761 reservations could happen in a ad-hoc fashion at any
time, while ICANN delegations typically happen in batches, and
the latest gTLD round is closed. Note: the ICANN gTLD
application process is described in the applicant guide book
[GUIDEBOOK].
4. The major risk is having a conflict when both the IETF and ICANN
want to use the same or similar strings. There exist no defined
cooperation between ICANN and IETF to avoid this problem.
5. There might be limited concerns if IETF were to reserve a string
outside of an ICANN gTLD round. The next ICANN gTLD applicant
book would simply refer to the existing list at publication time.
However, there is a possibility of conflict if an IETF
reservation were to happen during an ICANN gTLD round. A
hypothetical case study could be somebody trying a denial of
service attack early in the ICANN application process by asking
the IETF to reserved a string sought after by a competitor.
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5. Security Considerations
This document aims to provide a problem statement that will inform
future work. While security and privacy are fundamental
considerations, this document expects that future work will include
such analysis, and hence no attempt is made to do so here. See among
other places [SAC-057]
Reserving names has been presented as a way to prevent leakage into
the DNS. However, instructing resolvers to not forward the queries
(and/or by instructing authoritative servers not to respond) is not a
guarantee that such leakage will be prevented. The security (or
privacy) of an application MUST NOT rely on names not being exposed
to the Internet DNS resolution system.
6. IANA Considerations
This document has no IANA actions.
7. Acknowledgements
Thanks to Paul Hoffman for a large amount of editing.
8. References
8.1. Normative References
[IANA-SPECIAL-USE]
IANA, "Special-Use Domain Names", 2016,
<https://www.iana.org/assignments/special-use-domain-
names>.
[RFC2860] Carpenter, B., Baker, F., and M. Roberts, "Memorandum of
Understanding Concerning the Technical Work of the
Internet Assigned Numbers Authority", RFC 2860,
DOI 10.17487/RFC2860, June 2000,
<http://www.rfc-editor.org/info/rfc2860>.
[RFC6761] Cheshire, S. and M. Krochmal, "Special-Use Domain Names",
RFC 6761, DOI 10.17487/RFC6761, February 2013,
<http://www.rfc-editor.org/info/rfc6761>.
[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
DOI 10.17487/RFC6762, February 2013,
<http://www.rfc-editor.org/info/rfc6762>.
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[RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking
Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
2016, <http://www.rfc-editor.org/info/rfc7788>.
8.2. Informative References
[GUIDEBOOK]
ICANN, "gTLD Application Guidebook", June 2012,
<https://newgtlds.icann.org/en/applicants/agb/guidebook-
full-04jun12-en.pdf>.
[HUSTON] Huston, G., "What's in a Name?", December 2015,
<http://www.circleid.com/posts/20151222_whats_in_a_name/>.
[I-D.lewis-domain-names]
Lewis, E., "Domain Names", draft-lewis-domain-names-02
(work in progress), January 2016.
[NEW-GTLD]
ICANN, "New Generic Top-Level Domains", 2016,
<https://newgtlds.icann.org/>.
[SAC-057] ICANN Security and Stability Advisory Committee, "SSAC
Advisory on Internal Name Certificates", March 2013,
<https://www.icann.org/en/system/files/files/sac-
057-en.pdf>.
Appendix A. Editorial Notes
This section (and sub-sections) to be removed prior to publication.
A.1. Venue
An appropriate forum for discussion of this draft is for now the
DNSOP WG.
A.2. Change History
A.2.1. draft-adpkja-special-names-problem-00
Initial draft circulated for comment.
Appendix B. Change history
[ RFC Editor: Please remove this section before publication]
-01 to -02:
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o A very large number of readability / grammar / reference fixes
from Paul Hoffman.
-00 to -01:
o Significant readability changes.
-00:
o Initial draft circulated for comment.
Authors' Addresses
Geoff Huston
APNIC
Email: gih@apnic.net
Peter Koch
DENIC eG
Kaiserstrasse 75-77
Frankfurt 60329
Germany
Email: pk@denic.de
Alain Durand
ICANN
Email: alain.durand@icann.org
Warren Kumari
Google
Email: warren@kumari.net
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