Internet DRAFT - draft-jabley-multicast-ptr
draft-jabley-multicast-ptr
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
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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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