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The ALT Special Use Top Level Domain

The information below is for an old version of the document.
Document Type This is an older version of an Internet-Draft whose latest revision is Replaced
Authors Warren "Ace" Kumari , Andrew Sullivan
Last updated 2014-02-10
Replaced by draft-ietf-dnsop-alt-tld
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Stream Stream state (No stream defined)
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IESG IESG state I-D Exists
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dnsop                                                          W. Kumari
Internet-Draft                                                    Google
Intended status: Informational                               A. Sullivan
Expires: August 14, 2014                                             Dyn
                                                       February 10, 2014

                  The ALT Special Use Top Level Domain


   This document reserves a string to be used as a TLD label in non-DNS
   contexts.  [Ed note: By now you should be wildly confused.  Go read
   the intro / background :-P ]

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on August 14, 2014.

Copyright Notice

   Copyright (c) 2014 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
   ( in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements notation . . . . . . . . . . . . . . . . . .   2
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  The ALT namespace . . . . . . . . . . . . . . . . . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Appendix A.  Changes / Author Notes.  . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Lots of protocols and systems need to name entities, and the DNS
   "standard" of a series of labels separated with dots has become
   common, even in systems that are not actually part of the DNS.

   This document reserves the string "ALT" (short for Alternate) as a
   Special Use Domain ([RFC6761]) that should be used in the right-most
   label position to signify that this name is not rooted in the DNS,
   and that normal registration and lookup rules do not apply.

1.1.  Requirements notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].

1.2.  Terminology

   This document assumes familiarity with DNS terms and concepts.
   Please see [RFC1034] for background and concepts.

   o  DNS context: The namespace administered by ICANN.  This is the
      namespace / context that "normal" DNS uses.

   o  non-DNS context: Any other / alternate namespace.

2.  Background

   The DNS is a tree, and so has a single root.  Conventionally, a name
   immediately beneath the root is called a "Top Level Domain" or "TLD".
   TLDs usually delegate portions of their namespace to others, who may

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   then delegate further.  The hierarchical, distributed, caching nature
   of the DNS has made it the primary resolution system on the Internet.

   The success of the DNS means makes it a natural starting point for
   systems that need to name entities in a non-DNS context.  These name
   resolutions occur in a namespace distinct from the DNS.  A number of
   good examples of these sorts of systems are documented in Special-Use
   Domain Names of Peer-to-Peer Systems

   In many cases, these systems build a DNS style tree parallel to the
   global DNS administered by IANA.  They often use a pseudo-TLD to
   cause resolution in this alternate namespace, using things like
   browser plugins, shims in the name resolution process, or simply
   applications only use this alternate namespace.

   In many cases the creators of these alternate namespaces have simply
   chosen a convenient / descriptive string and started using this.
   These new strings are "alternate" strings, and not actually
   registered anywhere or part of the DNS.  However they appear to be
   TLDs, as they are the in the right-most position of a name.  Issues
   may arise if they are looked up in the DNS.  These include:

   o  User confusion: If someone emails a link of the form
      .pseudo-TLD to someone who does not have the necessary software to
      resolve names in the pseudo-TLD namespace, they may become

   o  Excess traffic hitting the DNS root.  Lookups may leak out of the
      pseudo-TLD namespace and end up hitting the DNS root nameservers.

   o  Collisions.  If the pseudo-TLD is eventually delegated from the
      root zone the behavior may be non-deterministic.

   o  Lack of success for the user's original goal.

3.  The ALT namespace

   In order to avoid the above issues we reserve the .ALT label.  This
   label should be used as a pseudo-TLD (in the right most (TLD)
   position of a name) to signify that this is an alternate (non-DNS)

   Alternate namespaces should differentiate themselves from other
   alternate namespaces by choosing a name and using it in the label
   position just before the pseudo-TLD.  For example, a group wishing
   create a namespace for [TODO(?): Need something better] Friends Of

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   Olaf they may choose the string "foo" and use any set of labels under

   As they are in an alternate namespace they have no significance in
   the regular DNS context and so should not be looked up in the DNS
   context.  Unfortunately simply saying that "something should not
   happen" doesn't actually stop it from happening, so we need some
   rules to deal with these.

   1.  Stub resolvers MAY elect not to send queries to any upstream
       resolver for names in the ALT TLD.

   2.  Iterative resolvers SHOULD follow the advice in [RFC6303],
       Section 3.

   3.  The root zone nameservers should either return NXDOMAIN
       responses, or the ALT TLD should be delegated to "new style"
       AS112 nameservers.  (TODO(WK): WK, JA, BD to revive AS112 /

   Groups wishing to create alternate namespaces SHOULD create their
   alternate namespace "under" a label that names their namespace, and
   "under" the ALT label.  They SHOULD choose a label that they expect
   to be unique / descriptive.  As there is no registry for the ALT
   namespace uniqueness is not guaranteed.

   Currently deployed projects and protocols that are using pseudo-TLDs
   (for example, the ".onion" pseudo-TLD (and other labels in
   [I-D.grothoff-iesg-special-use-p2p-names]) are not expected to move
   under the ALT TLD (but may do so if they wish; this is a common
   resource).  Rather, the ALT TLD is being reserved so that future
   projects of a similar nature have a designated place to create
   alternate resolution namespaces that will not conflict with the
   regular DNS context.

4.  IANA Considerations

   The IANA is requested to add the ALT string to the "Special-Use
   Domain Name" registry ([RFC6761], and reference this document.  In
   addition, the "Locally Served DNS Zones" ([RFC6303]) registry should
   be updated to reference this document.

   [ Ed: There are two options here.  Option 1: We could ask the IANA to
   run a "First Come First Served" registry for labels under the ALT
   TLD.  By registry I mean a "standard" IANA registry, not a registry
   in the DNS sense of the word (IANA would publish on a webpage "Foo | | Used for the foo project").  Option 2: This is a
   fully uncoordinated space (in the same way that people have been

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   picking pseudo-TLDs up till now) -- pick something that, as far as
   you know other's are not using... There are pros and cons to both --
   I don't want to overload the IANA, have people stage a land-grab for
   names, or give the impression that this is a "real" TLD.  Thoughts?
   Currently we say there is no registry (Section 3), but that can be

5.  Security Considerations

   One of the motivators for the creation of the alt pseudo-TLD is that
   unmanaged labels in the managed root name space are subject to
   unexpected takeover if the manager of the root name space decides to
   delegate the unmanaged label.

   The unmanaged and registry-free nature of labels beneath .ALT
   provides the opportunity for an attacker to re-use the chosen label
   and thereby possibly compromise applications dependent on the special
   host name.

6.  Acknowledgements

   The authors understand that there is much politics surrounding the
   delegation of a new TLD and thank the ICANN liaison (and any other
   poor sod who gets sucked into this) in advance.

7.  References

7.1.  Normative References

              Grothoff, C., Wachs, M., hellekin, h., and J. Appelbaum,
              "Special-Use Domain Names of Peer-to-Peer Systems", draft-
              grothoff-iesg-special-use-p2p-names-01 (work in progress),
              December 2013.

              IANA, "Autonomous System (AS) Numbers",

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, November 1987.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC6303]  Andrews, M., "Locally Served DNS Zones", BCP 163, RFC
              6303, July 2011.

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   [RFC6761]  Cheshire, S. and M. Krochmal, "Special-Use Domain Names",
              RFC 6761, February 2013.

7.2.  Informative References

              Manderson, T., Vegoda, L., and S. Kent, "RPKI Objects
              issued by IANA", draft-ietf-sidr-iana-objects-03 (work in
              progress), May 2011.

Appendix A.  Changes / Author Notes.

   [RFC Editor: Please remove this section before publication ]

   From -00 to -01.

   o  Nothing changed in the template!

Authors' Addresses

   Warren Kumari
   1600 Amphitheatre Parkway
   Mountain View, CA  94043


   Andrew Sullivan
   150 Dow Street
   Manchester, NH  03101


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