draft-jabley-multicast-ptr-00.txt

Network Working Group                                           J. Abley
Internet-Draft                                                 Dyn, Inc.
Intended status: BCP                                    October 18, 2013
Expires: April 21, 2014


              DNS Reverse Mapping for Multicast Addresses
                     draft-jabley-multicast-ptr-00

Abstract

   The mapping of IPv4 and IPv6 addresses to names using the Domain Name
   System (DNS) is colloquially known as "Reverse Mapping".  Reverse
   Mapping support for registered multicast address assignments in IPv4
   is currently incomplete and ad-hoc; in IPv6 there is no support at
   all.

   This document describes procedures to be followed that will result in
   more systematic and predictable support for Reverse Mapping for IPv4
   multicast address assignments, and introduces analogous support for
   IPv6.

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 http://datatracker.ietf.org/drafts/current/.

   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 April 21, 2014.

Copyright Notice

   Copyright (c) 2013 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



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   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.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  General Approach . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Naming Scheme  . . . . . . . . . . . . . . . . . . . . . . . .  5
     3.1.  IPv4 Multicast Addresses . . . . . . . . . . . . . . . . .  5
     3.2.  IPv6 Multicast Addresses . . . . . . . . . . . . . . . . .  5
   4.  Use of MCAST.ARPA  . . . . . . . . . . . . . . . . . . . . . .  6
   5.  IAB Considerations . . . . . . . . . . . . . . . . . . . . . .  7
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  8
     6.1.  Registry Changes . . . . . . . . . . . . . . . . . . . . .  8
       6.1.1.  IPv6 Multicast Scope Registry  . . . . . . . . . . . .  8
       6.1.2.  IPv4 Multicast Address Space Registries  . . . . . . .  8
       6.1.3.  IPv6 Multicast Address Space Registries  . . . . . . .  9
     6.2.  Delegation of MCAST.ARPA and MCAST6.ARPA . . . . . . . . .  9
     6.3.  Initial Zone Contents  . . . . . . . . . . . . . . . . . .  9
     6.4.  Process Changes  . . . . . . . . . . . . . . . . . . . . . 11
     6.5.  Ongoing Support for MCAST.NET  . . . . . . . . . . . . . . 11
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 15
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 15
   Appendix A.  Editorial Notes . . . . . . . . . . . . . . . . . . . 16
     A.1.  Change History . . . . . . . . . . . . . . . . . . . . . . 16
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 17


















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1.  Introduction

   The Domain Name System (DNS), as originally specified in [RFC1034]
   and [RFC1035], provides support for the mapping of IPv4 addresses to
   names using a namespace convention within the IN-ADDR.ARPR domain and
   the PTR resoure record type.

   The analogous mapping of IPv6 address to names is specified in
   [RFC3596], adopting a similar namespace convention within the
   IP6.ARPA domain.

   Multicast addresses are assigned by the IANA, and assignments are
   documented in various IANA registries.

   For IPv4, Reverse Mapping of assigned multicast addresses to names
   has historically been provided in an ad-hoc and incomplete fashion,
   without tight coordination with IANA multicast address assignment
   processes.  Names assigned to IPv4 multicast addresses have been
   chosen somewhat arbitrarily within the MCAST.NET domain.  For IPv6,
   no Reverse Mapping is provided.

   This document describes procedures to be followed by the IANA to
   support predictable and consistent Reverse Mapping for registered
   multicast addresses in IPv4 and IPv6.



























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2.  General Approach

   This document specifies extensions to existing IPv4 and IPv6
   multicast registries to include a mandatory column "DNS Label".  This
   field is required to be popluated with a unique, valid DNS label for
   all future multicast address assignments except in the case where
   reverse mapping for an address is explicitly not desirable.

   The procedures at the IANA relating to multicast address assignment
   are extended to include the provisioning of appropriate changes in
   the DNS at the time of registration or de-registration of any
   multicast addresses.  Specific actions requested of the IANA are
   described in Section 6.

   Names for multicast addresses are assigned under MCAST.ARPA for IPv4
   addresses, and MCAST6.ARPA for IPv6 addresses.  The naming schemes to
   bs used in each case are described in Section 3.  The use of
   MCAST.ARPA rather than MCAST.NET is discussed in Section 4.

































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3.  Naming Scheme

3.1.  IPv4 Multicast Addresses

   Each assigned IPv4 multicast address has an accompanying DNS Label.
   The name associated with an IPv4 multicast address with DNS Label
   SOMENAME is SOMENAME.MCAST.ARPA.

   For example, suppose the assigned IPv4 multicast address 224.0.1.1
   has the DNS Label "NTP".  The address 224.0.1.1 maps to the name
   "NTP.MCAST.ARPA"; the name "NTP.MCAST.ARPA" maps to the address
   224.0.1.1.

3.2.  IPv6 Multicast Addresses

   Each assigned IPv6 multicast address has an accompanying DNS Label
   ("Address Label").

   IPv6 multicast addresses may be of fixed or variable scope.  The
   naming scheme for these addresses incorporates a scope identifier
   using an additional DNS label ("Scope Label"), specified in a
   dedicated registry (see Section 6.1.1).  Both fixed and variable
   scope multicast addresses use the same naming scheme.

   The name associated with an IPv6 multicast address with Scope Label
   SCOPE and Address Label SOMENAME is SOMENAME.SCOPE.MCAST6.ARPA.

   For example, suppose ff01::1 is an assigned IPv6 multicast address
   with Scope Label "NODE-LOCAL" and Address Label "ALL-NODES".  The
   address ff01::1 maps to the name "ALL-NODES.NODES-LOCAL.MCAST6.ARPA";
   the name "ALL-NODES.NODES-LOCAL.MCAST6.ARPA" maps to the address
   ff01::1.

   The variable-scope multicast address ff0x::fb will have different
   Reverse Mapping depending on the scope specified in the address (i.e.
   the value of x), although the Address Label in each case will be the
   same ("MDNSV6").  The Site-Local address ff05::fb has an associated
   Scope Label "SITE-LOCAL", and is therefore named MDNSV6.SITE-
   LOCAL.MCAST6.ARPA.  The Link-Local address ff02::fb has an associated
   Scope Label "LINK-LOCAL" and hence is named MDNSV6.LINK-
   LOCAL.MCAST6.ARPA.










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4.  Use of MCAST.ARPA

   Use of the MCAST.ARPA domain rather than MCAST.NET for IPv4 multicast
   addresses is specified for the same reasons that led IP6.INT to be
   superceded by "IP6.ARPA" [RFC3152].

   It is prudent to assume that hard-coded assumptions about names in
   MCAST.NET exist, and will persist for some time.  This document
   specifies that names in the MCAST.ARPA domain also be available in
   the MCAST.NET domain, to provide support for software with those
   assumptions.  Ongoing support for the MCAST.NET zone is described in
   Section 6.5.

   It is possible that in the future empirical measurement will confirm
   that the use of names under MCAST.NET is no longer required and that
   provisioning of the MCAST.NET domain can safely cease.  This document
   provides no such measurement and makes no such recommendation,
   however.

































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5.  IAB Considerations

   This document proposes a delegation within the ARPA domain, and, in
   accordance with [RFC3172], IAB review and approval of the delegation
   of MCAST.ARPA and MCAST6.ARPA as described in Section 6.2 is
   required.

   Once IAB approval has been obtained, this section may be removed
   prior to publication or updated to include text that confirms the
   IAB's decision, at the IAB's discretion.









































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6.  IANA Considerations

6.1.  Registry Changes

6.1.1.  IPv6 Multicast Scope Registry

   The IANA is directed to create a new registry as follows:

   Registry Name:  IPv6 Multicast Address Scopes

   Registration Procedure:  Standards Action

   Reference:  This document

   Schema:  See initial contents, below.  Note that the Scope Value and
      DNS Label fields are mandatory for all rows, and that values
      chosen for future DNS Label fields are required to be unique
      within this registry.

   The initial contents of this new registry should be:

   +-------------+-------------+--------------------------+-----------+
   | Scope Value | DNS Label   | Scope Name               | Reference |
   +-------------+-------------+--------------------------+-----------+
   | 0x0         | (none)      | Reserved                 | [RFC4291] |
   |             |             |                          |           |
   | 0x1         | NODE-LOCAL  | Node-Local Scope         | [RFC4291] |
   |             |             |                          |           |
   | 0x2         | LINK-LOCAL  | Link-Local Scope         | [RFC4291] |
   |             |             |                          |           |
   | 0x3         | (none)      | Reserved                 | [RFC4291] |
   |             |             |                          |           |
   | 0x4         | ADMIN-LOCAL | Admin-Local Scope        | [RFC4291] |
   |             |             |                          |           |
   | 0x5         | SITE-LOCAL  | Site-Local Scope         | [RFC4291] |
   |             |             |                          |           |
   | 0x8         | ORG-LOCAL   | Organisation-Local Scope | [RFC4291] |
   |             |             |                          |           |
   | 0xE         | GLOBAL      | Global Scope             | [RFC4291] |
   +-------------+-------------+--------------------------+-----------+

   The IANA may add "Date Registered" and "Last Revised" columns to the
   schema at its discretion.

6.1.2.  IPv4 Multicast Address Space Registries

   The IANA is directed to add a mandatory "DNS Label" column to all
   IPv4 Multicast Address Space registries.  The initial contents of the



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   DNS Label field for each row should be taken from the corresponding
   MCAST.NET zone owner names where available; addresses with no
   existing mapping in MCAST.NET should have DNS Labels assigned by the
   IANA at their discretion.

   All existing assignments should have a DNS Label assigned.  A DNS
   Label should be mandatory for all future registrations.  DNS Labels
   are required to be unique for all IPv4 multicast address assignments.

6.1.3.  IPv6 Multicast Address Space Registries

   The IANA is directed to add a mandatory "DNS Label" column to all
   IPv6 Multicast Address Space registries.  The initial contents of the
   DNS Label field for each row should be assigned by the IANA at their
   discretion.

   All existing assignments should have a DNS Label assigned.  A DNS
   Label should be mandatory for all future registrations.  DNS Labels
   are required to be unique for all IPv6 multicast address assignments.

6.2.  Delegation of MCAST.ARPA and MCAST6.ARPA

   The IANA is directed to create and host the MCAST.ARPA and
   MCAST6.ARPA zones on name servers of their choosing.  The MCAST.ARPA
   and MCAST6.ARPA zones should be signed using DNSSEC, with DNSSEC
   parameters chosen by the IANA.  The initial zone contents should be
   as described in Section 6.3.

   The IANA is directed to provision secure delegations for the
   MCAST.ARPA and MCAST6.ARPA zones from the ARPA zone (i.e. delegations
   with accompanying DS RRSets).

6.3.  Initial Zone Contents

   The IANA is directed to populate the MCAST.ARPA and MCAST6.ARPA
   zones, and the corresponding reverse mapping zones under IN-ADDR.ARPA
   and IP6.ARPA, directly from the IPv4 and IPv6 Multicast Address
   Registries, amended as described in Section 6.1.

   As an example, if the IPv6 Variable Scope Multicast Addresses sub-
   registry contained the following entry:

                 +-------------+-------------+-----------+
                 | Address(es) | Description | DNS Label |
                 +-------------+-------------+-----------+
                 | FF0X::FB    | mDNSv6      | MDNSV6    |
                 +-------------+-------------+-----------+




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   then the following DNS records would be required:

     $ORIGIN MCAST6.ARPA.
     ;
     ; all scoped addresses for mDNSv6
     ;
     MDNSV6.NODE-LOCAL       AAAA    FF01::FB
     MDNSV6.LINK-LOCAL       AAAA    FF02::FB
     MDNSV6.ADMIN-LOCAL      AAAA    FF04::FB
     MDNSV6.SITE-LOCAL       AAAA    FF05::FB
     MDNSV6.ORG-LOCAL        AAAA    FF08::FB
     MDNSV6.GLOBAL           AAAA    FF0E::FB

     $ORIGIN 0.F.F.IP6.ARPA.
     ;
     ; all scoped addresses for mDNSv6 (split across lines for clarity)
     ;
     B.F.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1 \
       PTR MDNSV6.NODE-LOCAL.MCAST6.ARPA.
     B.F.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2 \
       PTR MDNSV6.LINK-LOCAL.MCAST6.ARPA.
     B.F.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.4 \
       PTR MDNSV6.ADMIN-LOCAL.MCAST6.ARPA.
     B.F.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.5 \
       PTR MDNSV6.SITE-LOCAL.MCAST6.ARPA.
     B.F.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8 \
       PTR MDNSV6.ORG-LOCAL.MCAST6.ARPA.
     B.F.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.E \
       PTR MDNSV6.GLOBAL.MCAST6.ARPA.

   As a further example, if the IPv4 Internetwork Control Block
   Multicast Address Registry contained the following entry:

                +-------------+--------------+-----------+
                | Address(es) | Description  | DNS Label |
                +-------------+--------------+-----------+
                | 224.0.1.2   | SGI-Dogfight | SGI-DOG   |
                +-------------+--------------+-----------+

   then the following DNS records would be required:











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     $ORIGIN MCAST.ARPA.
     ;
     ; SGI-Dogfight address
     ;
     SGI-DOG                 A       224.0.1.2

     $ORIGIN 224.IN-ADDR.ARPA.
     ;
     ; SGI-Dogfight address
     ;
     2.1.0                   PTR     SGI-DOG.MCAST.ARPA.

6.4.  Process Changes

   The IANA is directed to require a valid and unique DNS Label to be
   specified within the existing processes of multicast address
   assignment in IPv4 and IPv6.

   The IANA is further directed to maintain the MCAST.ARPA, MCAST6.ARPA
   and related domains under IP6.ARPA and IN-ADDR.ARPA such that any
   additions, changes or deletions from the corresponding address
   registries are reflected accurately in the DNS.

6.5.  Ongoing Support for MCAST.NET

   IANA is directed to remove all non-apex resource records from the
   MCAST.NET zone and to add an apex DNAME [RFC6672] with target
   MCAST.ARPA.  The intention is to provide backwards compatibility for
   software that has hard-coded assumptions about naming conventions for
   IPv4 multicast addresses.

   For example, the following describes the result of this change for
   MCAST.NET SOA serial 2012123836, with DNSSEC resource records omitted
   for clarity:

















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     $ORIGIN MCAST.NET.

     ; beginning of zone

     @       SOA     SNS.DNS.ICANN.ORG. NOC.DNS.ICANN.ORG. (
                             2012123836
                             7200
                             3600
                             604800
                             3600 )

             NS      A.IANA-SERVERS.NET.
             NS      B.IANA-SERVERS.NET.
             NS      C.IANA-SERVERS.NET.
             NS      NS.ICANN.ORG.

             DNAME   MCAST.ARPA.

     ; end of zone
































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7.  Security Considerations

   This document presents no known additional security concerns to the
   Internet.















































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8.  Acknowledgements

   Your name here, etc.
















































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9.  References

9.1.  Normative References

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

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, November 1987.

   [RFC3596]  Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
              "DNS Extensions to Support IP Version 6", RFC 3596,
              October 2003.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, February 2006.

9.2.  Informative References

   [RFC3152]  Bush, R., "Delegation of IP6.ARPA", BCP 49, RFC 3152,
              August 2001.

   [RFC3172]  Huston, G., "Management Guidelines & Operational
              Requirements for the Address and Routing Parameter Area
              Domain ("arpa")", BCP 52, RFC 3172, September 2001.

   [RFC6672]  Rose, S. and W. Wijngaards, "DNAME Redirection in the
              DNS", RFC 6672, June 2012.























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Appendix A.  Editorial Notes

   This section (and sub-sections) to be removed prior to publication.

A.1.  Change History

   00 Initial draft, circulated for the purposes of entertainment.












































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Author's Address

   Joe Abley
   Dyn, Inc.
   470 Moore Street
   London, ON  N6C 2C2
   Canada

   Phone: +1 519 670 9327
   Email: jabley@dyn.com









































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