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Versions: (draft-xli-v6ops-ivi-icmp-address) 00 01 02 03 04 05 06 07 RFC 6791

Network Working Group                                              X. Li
Internet-Draft                                                    C. Bao
Intended status: BCP                              CERNET Center/Tsinghua
Expires: January 4, 2013                                      University
                                                                 D. Wing
                                                        R. Vaithianathan
                                                                   Cisco
                                                               G. Huston
                                                                   APNIC
                                                            July 3, 2012


          Stateless Source Address Mapping for ICMPv6 Packets
                  draft-ietf-v6ops-ivi-icmp-address-02

Abstract

   A stateless IPv4/IPv6 translator may receive ICMPv6 packets
   containing non IPv4-translatable addresses as the source that should
   be passed across the translator as an ICMP packet directed to the
   IPv4-translatable destination.  This document presents
   recommendations for source address translation in ICMPv6 headers for
   such cases.

Status of this Memo

   This Internet-Draft is submitted to IETF 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 January 4, 2013.

Copyright 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
   Provisions Relating to IETF Documents



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   (http://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  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Notational Conventions  . . . . . . . . . . . . . . . . . . . . 3
   3.  Problem Statement and Considerations  . . . . . . . . . . . . . 3
   4.  ICMP Extension  . . . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Stateless Address Mapping Algorithm . . . . . . . . . . . . . . 4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 4
   9.  Normative References  . . . . . . . . . . . . . . . . . . . . . 5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5






























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1.  Introduction

   The IP/ICMP translation document of IPv4/IPv6 translation [RFC6145]
   states that "the IPv6 addresses in the ICMPv6 header may not be IPv4-
   translatable addresses and there will be no corresponding IPv4
   addresses represented of this IPv6 address.  In this case, the
   translator can do stateful translation.  A mechanism by which the
   translator can instead do stateless translation is left for future
   work."  This document presents recommendations for this case.


2.  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 (for
   example "Packet Too Big") sourced from an non-IPv4-translatable IPv6
   address, directed to an IPv4-translatable IPv6 address, it needs to
   generate an ICMP message.  For the reasons discussed below, choosing
   the source IPv4 address of this ICMP message is problematic.

   The address used should not cause the ICMP packet to be a candidate
   for discarding, particularly in the contest of uRPF filters
   [RFC3704].  This consideration precludes the use of private IPv4
   address space [RFC1918] in this context.

   It is also a consideration that the IPv4/IPv6 translation is intended
   for use in contexts where IPv4 addresses may not be readily
   available, so it is not considered to be appropriate to use IPv4-
   translatable IPv6 addresses for all internal points in the IPv6
   network that may originate ICMPv6 messages.

   It is also an objective that it is possible for the IPv4 recipient of
   the ICMP message be able to distinguish between different IPv6 ICMPv6
   originations (for example, to support a traceroute diagnostic utility
   that provides some limited network level visibility across the IPv4/
   IPv6 translator).  This implies that an IPv4/IPv6 translator needs to
   have a pool of IPv4 addresses for mapping the source address of
   ICMPv6 packets generated from different originations, or to include
   the IPv6 source address information for mapping the source address by
   others means.

   These considerations leads to the recommendation of using the a



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   single (or small pool) of public IPv4 address as the source address
   of translated ICMP and using ICMP extension [RFC5837] to include IPv6
   address as Interface IP Address Sub-Object.


4.  ICMP Extension

   No matter a single public IPv4 address (in the IPv4 interface or a
   loopback address of the translator) or a pool of public IPv4
   addresses are used, the translator SHOULD implement ICMP extension
   defined by [RFC5837].  The resulting ICMP extension SHOULD include
   the Interface IP Address Sub-Object that specify the source IPv6
   addresses in the original ICMPv6.  When an enhanced traceroute
   application is used, it can get the real IPv6 source addresses which
   generate the ICMPv6 messages.  Therefore, it is able to traceback to
   their origins and take filtering/rate-limiting actions if necessary.


5.  Stateless Address Mapping Algorithm

   If a pool of public IPv4 addresses is configured in the translator,
   it is RECOMMENDED to randomly pick up the IPv4 public address in the
   pool.  This can somehow avoid the appearance of a routing loop to
   tools such as traceroute.  An enhanced traceroute application is
   still RECOMMENDED in order to obtain the real IPv6 source addresses
   which generate the ICMPv6 messages.


6.  Security Considerations

   This document does not introduce any new security considerations.


7.  IANA Considerations

   None.


8.  Acknowledgments

   The authors would like to acknowledge the following contributors of
   this document: Kevin Yin, Chris Metz and Neeraj Gupta.  The authors
   would also like to thank Ronald Bonica, Ray Hunter, George Wes, Yu
   Guanghui, Sowmini Varadhan, David Farmer, Fred Baker, Leo Vegoda,
   Joel Jaeggli, Henrik Levkowetz, Henrik Levkowetz, Randy Bush and
   Warren Kumari for their comments and suggestions.





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9.  Normative References

   [RFC1918]  Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
              E. Lear, "Address Allocation for Private Internets",
              BCP 5, RFC 1918, February 1996.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3704]  Baker, F. and P. Savola, "Ingress Filtering for Multihomed
              Networks", BCP 84, RFC 3704, March 2004.

   [RFC4443]  Conta, A., Deering, S., and M. Gupta, "Internet Control
              Message Protocol (ICMPv6) for the Internet Protocol
              Version 6 (IPv6) Specification", RFC 4443, March 2006.

   [RFC5837]  Atlas, A., Bonica, R., Pignataro, C., Shen, N., and JR.
              Rivers, "Extending ICMP for Interface and Next-Hop
              Identification", RFC 5837, April 2010.

   [RFC6145]  Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
              Algorithm", RFC 6145, April 2011.


Authors' Addresses

   Xing Li
   CERNET Center/Tsinghua University
   Room 225, Main Building, Tsinghua University
   Beijing  100084
   CN

   Phone: +86 10-62785983
   Email: xing@cernet.edu.cn


   Congxiao Bao
   CERNET Center/Tsinghua University
   Room 225, Main Building, Tsinghua University
   Beijing  100084
   CN

   Phone: +86 10-62785983
   Email: congxiao@cernet.edu.cn







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   Dan Wing
   Cisco Systems, Inc.
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   Email: dwing@cisco.com


   Ramji Vaithianathan
   Cisco Systems, Inc.
   A 5-2, BGL 12-4, SEZ Unit,
   Cessna Business Park, Varthur Hobli
   Sarjapur Outer Ring Road
   BANGALORE  KARNATAKA 560 103
   INDIA

   Phone: +91 80 4426 0895
   Email: rvaithia@cisco.com


   Geoff Huston
   APNIC

   Email: gih@apnic.net


























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