Internet Engineering Task Force (IETF) X. Li
Request for Comments: 6791 C. Bao
Updates: 6145 CERNET Center/Tsinghua University
Category: Standards Track D. Wing
ISSN: 2070-1721 R. Vaithianathan
Cisco
G. Huston
APNIC
November 2012
Stateless Source Address Mapping for ICMPv6 Packets
Abstract
A stateless IPv4/IPv6 translator may receive ICMPv6 packets
containing non-IPv4-translatable addresses as the source. These
packets should be passed across the translator as ICMP packets
directed to the IPv4 destination. This document presents
recommendations for source address translation in ICMPv6 headers to
handle such cases.
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 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/rfc6791.
Li, et al. Standards Track [Page 1]RFC 6791 Source Address Mapping for ICMPv6 November 2012Copyright Notice
Copyright (c) 2012 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
3. Problem Statement and Considerations . . . . . . . . . . . . . 3
3.1. Considerations . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Recommendations . . . . . . . . . . . . . . . . . . . . . . 3
4. ICMP Extension . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Stateless Address Mapping Algorithm . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . . 5
1. Introduction
Section 5.3 of "IP/ICMP Translation Algorithm" [RFC6145] states that
"the IPv6 addresses in the IPv6 header may not be IPv4-translatable
addresses and there will be no corresponding IPv4 addresses
representing this IPv6 address. In this case, the translator can do
stateful translation. A mechanism by which the translator can
instead do stateless translation of this address is left for future
work." This document, "Stateless Source Address Mapping for ICMPv6
Packets", provides recommendations for this case.
For the purposes of this document, the term "IPv4-translatable IPv6
address" is as defined in Section 2.2 of [RFC6052].
Li, et al. Standards Track [Page 2]RFC 6791 Source Address Mapping for ICMPv6 November 20122. Notational Conventions
The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
document, are to be interpreted as described in [RFC2119].
3. Problem Statement and Considerations
When a stateless IPv4/IPv6 translator receives an ICMPv6 message
[RFC4443] (for example, "Packet Too Big") sourced from a non-IPv4-
translatable IPv6 address and bound for an IPv4-translatable IPv6
datatracker.ietf.org