Internet Engineering Task Force (IETF) S. Jiang
Request for Comments: 6563 Huawei Technologies Co., Ltd
Category: Informational D. Conrad
ISSN: 2070-1721 Cloudflare, Inc.
B. Carpenter
Univ. of Auckland
March 2012
Moving A6 to Historic Status
Abstract
This document provides a summary of issues related to the use of A6
records, discusses the current status, and moves RFC 2874 to Historic
status, providing clarity to implementers and operators.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6563.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Jiang, et al. Informational [Page 1]RFC 6563 Moving A6 to Historic Status March 2012Table of Contents
1. Introduction and Background .....................................2
1.1. Standards Action Taken .....................................3
2. A6 Issues .......................................................3
2.1. Resolution Latency .........................................3
2.2. Resolution Failure .........................................3
2.3. Cross Administrative Domains ...............................4
2.4. Difficult Maintenance ......................................4
2.5. Existence of Multiple RR Types for One Purpose is Harmful ..4
2.6. Higher Security Risks ......................................4
3. Current Usage of A6 .............................................5
3.1. Reasons for Current A6 Usage ...............................5
4. Moving A6 to Historic Status ....................................6
4.1. Impact on Current A6 Usage .................................6
4.2. Transition Phase for Current A6 Usage ......................6
5. Security Considerations .........................................6
6. IANA Considerations .............................................6
7. Acknowledgments .................................................6
8. References ......................................................7
8.1. Normative References .......................................7
8.2. Informative References .....................................7
1. Introduction and Background
The IETF began standardizing two different DNS protocol enhancements
for IPv6 addresses in DNS records: AAAA was specified in 1995 as a
Proposed Standard [RFC1886] and later in 2003 as a Draft Standard
[RFC3596], and A6 appeared in 2000 as a Proposed Standard [RFC2874].
The existence of multiple ways to represent an IPv6 address in the
DNS has led to confusion and conflicts about which of these protocol
enhancements should be implemented and/or deployed. Having more than
one choice of how IPv6 addresses are to be represented within the DNS
can be argued to have led to delays in the deployment of IPv6. In
2002, "Representing Internet Protocol version 6 (IPv6) Addresses in
the Domain Name System (DNS)" [RFC3363] moved A6 to Experimental
status, with an aim of clearing up any confusion in this area.
[RFC3363] and [RFC3364] compared AAAA and A6, and examined many of
the issues in the A6 standard; these issues are summarized in this
datatracker.ietf.org