Behave WG                                                  T. Savolainen
Internet-Draft                                                     Nokia
Intended status: Informational                               J. Korhonen
Expires: March 28, 2011                           Nokia Siemens Networks
                                                      September 24, 2010


        Heuristic discovery of NAT64 and Network-Specific Prefix
           draft-savolainen-heuristic-nat64-discovery-00.txt

Abstract

   Advanced hosts and applications benefit of the knowledge of an IPv6
   address, AAAA record, synthesis taking place in the network.  This
   draft describes a method for detecting presence of NAT64 and for
   learning Network-Specific Prefix used in the access network without
   support from the access network.  The method depends on existence of
   known IPv4-only domain name.  The information learned enables
   applications and hosts to to perform local IPv6 address synthesis and
   in some cases avoid NAT64.

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
   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 March 28, 2011.

Copyright Notice

   Copyright (c) 2010 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
   carefully, as they describe your rights and restrictions with respect



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   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.  Requirements and Terminology  . . . . . . . . . . . . . . . . . 3
     2.1.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Host behavior . . . . . . . . . . . . . . . . . . . . . . . . . 3
     3.1.  Connectivity test . . . . . . . . . . . . . . . . . . . . . 4
   4.  Hosting of an IPv4-only name(s) . . . . . . . . . . . . . . . . 4
   5.  Required IPv4 addresses . . . . . . . . . . . . . . . . . . . . 4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 5
   9.  Normative References  . . . . . . . . . . . . . . . . . . . . . 5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5































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.  Introduction

   As the networks transition to IPv6, connectivity to IPv4-only domains
   have to be provided.  NAT64 [I-D.ietf-behave-v6v4-xlate-stateful] and
   DNS64 [I-D.ietf-behave-dns64] technologies can be utilized to make
   IPv4-only peers look like being reachable over IPv6.  The DNS64
   utilizes IPv6 address synthesis to create local IPv6 presentations of
   peers having only IPv4 addresses.  Applications utilizing DNS for
   resolving peers' IPv6 addresses can work seamlessly through protocol
   translation taking place at NAT64.

   The DNS64 cannot serve applications not using DNS, such as those
   receiving IPv4 addresses as referrals.  Such applications could
   nevertheless be able to work through NAT64, provided they are able to
   create locally valid IPv6 presentations of peers' IPv4 addresses.

   This document describes a method for advanced applications to learn
   the information required to perform local IPv6 address synthesis.

   The knowledge of IPv6 address synthesizing taking place may also be
   useful if DNS64 is present in dual-stack network access.  In such
   cases hosts may choose to use IPv4 addresses instead of synthesized
   IPv6 addresses, and hence avoid traversal through NAT64.


.  Requirements and Terminology

2.1.  Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].


.  Host behavior

   A host requiring information for local IPv6 address synthesis or for
   NAT64 avoidance shall send a DNS query for AAAA record of a well-
   known IPv4-only fully qualified domain name.  This may happen, for
   example, at the moment the host is configured an IPv6 address of a
   DNS server.  This may also happen at the time first DNS query for
   AAAA record is initiated.

   If a host receives negative reply, it learns there are no NAT64 in
   the network.

   The host may also have to send a DNS query for the A record of the
   well-known IPv4-only fully qualified domain name, unless also the



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   IPv4 address is well-known by the host.

   If a host receives AAAA reply, it knows the network is utilizing IPv6
   address synthesis.  If the received IPv6 address has the well-known
   prefix, the host can use that information for local IPv6 address
   synthesis.  If the prefix is not a well-known the host shall search
   for the IPv4 address inside the received IPv6 address.

   The IPv4 address inside synthesized IPv6 address should be located at
   some of the locations described in [I-D.ietf-behave-address-format].
   If the IPv4 address is not found on any of the standard locations the
   network must be using different formatting.  In such case the host
   may try to find out the IPv4 address at some other location.

   The information required for local IPv6 address synthesis should be
   made available for applications to utilize.

3.1.  Connectivity test

   Once the host has found the IPv4 address within the received
   synthesized IPv6 address the host should locally synthesize another
   IPv6 address using another IPv4 address and test connectivity with
   it.  The connectivity test may be conducted e.g. with ICMPv6 or with
   a transport layer protocol.

   This test ensures local address synthetization results in functional
   and protocol translatable IPv6 addresses.


.  Hosting of an IPv4-only name(s)

   The required IPv4-only name for NAT64 discovery has to be hosted by
   someone.  While IANA(?) might host one(?), it may be safest for
   device and/or application vendors to host IPv4-only names for their
   own use.  Another name may be needed for connectivity test purposes.


.  Required IPv4 addresses

   Running a setup described herein requires two IPv4 addresses.  One
   for the known IPv4-only name and another one for local IPv6 address
   synthesis and connectivity test.


.  Security Considerations

   No security considerations have been identified.




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.  IANA Considerations

   IANA(?) should define a name and an IPv4 address for a well-known
   IPv4-only name.


.  Acknowledgements

   To be added.


.  Normative References

   [I-D.ietf-behave-address-format]
              Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
              Li, "IPv6 Addressing of IPv4/IPv6 Translators",
              draft-ietf-behave-address-format-10 (work in progress),
              August 2010.

   [I-D.ietf-behave-dns64]
              Bagnulo, M., Sullivan, A., Matthews, P., and I. Beijnum,
              "DNS64: DNS extensions for Network Address Translation
              from IPv6 Clients to IPv4 Servers",
              draft-ietf-behave-dns64-10 (work in progress), July 2010.

   [I-D.ietf-behave-v6v4-xlate-stateful]
              Bagnulo, M., Matthews, P., and I. Beijnum, "Stateful
              NAT64: Network Address and Protocol Translation from IPv6
              Clients to IPv4 Servers",
              draft-ietf-behave-v6v4-xlate-stateful-12 (work in
              progress), July 2010.

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


Authors' Addresses

   Teemu Savolainen
   Nokia
   Hermiankatu 12 D
   FI-33720 Tampere
   Finland

   Email: teemu.savolainen@nokia.com






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   Jouni Korhonen
   Nokia Siemens Networks
   Linnoitustie 6
   FI-02600 Espoo
   Finland

   Email: jouni.nospam@gmail.com












































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