Special Use Domain Name 'ipv4only.arpa'
RFC 8880
| Document | Type |
RFC - Proposed Standard
(August 2020; No errata)
Updates RFC 7050
Was draft-cheshire-sudn-ipv4only-dot-arpa (individual)
|
|
|---|---|---|---|
| Authors | Stuart Cheshire , David Schinazi | ||
| Last updated | 2020-08-31 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html xml pdf htmlized (tools) htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | (None) | |
| Document shepherd | Warren Kumari | ||
| Shepherd write-up | Show (last changed 2020-01-19) | ||
| IESG | IESG state | RFC 8880 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Warren Kumari | ||
| Send notices to | (None) | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) S. Cheshire
Request for Comments: 8880 Apple Inc.
Updates: 7050 D. Schinazi
Category: Standards Track Google LLC
ISSN: 2070-1721 August 2020
Special Use Domain Name 'ipv4only.arpa'
Abstract
NAT64 (Network Address and Protocol Translation from IPv6 Clients to
IPv4 Servers) allows client devices using IPv6 to communicate with
servers that have only IPv4 connectivity.
The specification for how a client discovers its local network's
NAT64 prefix (RFC 7050) defines the special name 'ipv4only.arpa' for
this purpose. However, in its Domain Name Reservation Considerations
section (Section 8.1), that specification (RFC 7050) indicates that
the name actually has no particularly special properties that would
require special handling.
Consequently, despite the well-articulated special purpose of the
name, 'ipv4only.arpa' was not recorded in the Special-Use Domain
Names registry as a name with special properties.
This document updates RFC 7050. It describes the special treatment
required and formally declares the special properties of the name.
It also adds similar declarations for the corresponding reverse
mapping names.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8880.
Copyright Notice
Copyright (c) 2020 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
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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
1.1. Conventions and Terminology
2. Reasons to Declare 'ipv4only.arpa' as Special
3. Consequences of 'ipv4only.arpa' Not Being Declared Special
3.1. Consequences for Name Resolution APIs and Libraries
3.2. Consequences for DNS64 Implementations
4. Remedies
5. Security Considerations
6. IANA Considerations
7. Domain Name Reservation Considerations
7.1. Special Use Domain Name 'ipv4only.arpa'
7.2. Names '170.0.0.192.in-addr.arpa' and
'171.0.0.192.in-addr.arpa'
7.2.1. ip6.arpa Reverse Mapping PTR Records
8. References
8.1. Normative References
8.2. Informative References
Appendix A. Example BIND 9 Configuration
Acknowledgements
Authors' Addresses
1. Introduction
NAT64 (Network Address and Protocol Translation from IPv6 Clients to
IPv4 Servers) [RFC6146] allows client devices using IPv6 to
communicate with servers that have only IPv4 connectivity.
DNS64 (DNS Extensions for Network Address Translation from IPv6
Clients to IPv4 Servers) [RFC6147] facilitates use of NAT64 by
clients by generating synthesized IPv6 addresses for IPv4 servers
that have no IPv6 address of their own, or by communicating the local
network's NAT64 prefix to clients so that they can perform the IPv6
address synthesis themselves.
The specification for how a client discovers its local network's
NAT64 prefix [RFC7050] defines the special name 'ipv4only.arpa' for
this purpose, but in its Domain Name Reservation Considerations
section (Section 8.1), that specification [RFC7050] indicates that
the name actually has no particularly special properties that would
require special handling and does not request IANA to record the name
in the Special-Use Domain Names registry [SUDN].
Consequently, despite the well-articulated special purpose of the
name, 'ipv4only.arpa' was not recorded in the Special-Use Domain
Names registry [SUDN] as a name with special properties.
This omission was discussed in the document "Special-Use Domain Names
Problem Statement" [RFC8244].
As a result of this omission, in cases where software needs to give
this name special treatment in order for it to work correctly, there
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