IPv6 Operations Working Group                               A. Matsumoto
Internet-Draft                                               T. Fujisaki
Intended status: Informational                                       NTT
Expires: October 30, 2008                                      R. Hiromi
                                                             K. Kanayama
                                                           Intec Netcore
                                                          April 28, 2008


             Requirements for address selection mechanisms
                draft-ietf-v6ops-addr-select-req-06.txt

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Copyright Notice

   Copyright (C) The IETF Trust (2008).

Abstract

   There are some problematic cases when using default address selection
   mechanism which RFC 3484 defines.  This document describes additional
   requirements co-working with RFC3484 to solve the problems.





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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Requirements of Address Selection . . . . . . . . . . . . . . . 3
     2.1.  Effectiveness . . . . . . . . . . . . . . . . . . . . . . . 3
     2.2.  Timing  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     2.3.  Dynamic Behavior Update . . . . . . . . . . . . . . . . . . 3
     2.4.  Node-Specific Behavior  . . . . . . . . . . . . . . . . . . 4
     2.5.  Application-Specific Behavior . . . . . . . . . . . . . . . 4
     2.6.  Multiple Interface  . . . . . . . . . . . . . . . . . . . . 4
     2.7.  Central Control . . . . . . . . . . . . . . . . . . . . . . 4
     2.8.  Next-hop Selection  . . . . . . . . . . . . . . . . . . . . 4
     2.9.  Compatibility with RFC 3493 . . . . . . . . . . . . . . . . 4
     2.10. Compatibility and Interoperability with RFC 3484  . . . . . 5
     2.11. Security  . . . . . . . . . . . . . . . . . . . . . . . . . 5
   3.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
     3.1.  List of threats introduced by new address-selection
           mechanism . . . . . . . . . . . . . . . . . . . . . . . . . 5
     3.2.  List of recommendations in which security mechanism
           should be applied . . . . . . . . . . . . . . . . . . . . . 5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     5.1.  Normative References  . . . . . . . . . . . . . . . . . . . 6
     5.2.  Informative References  . . . . . . . . . . . . . . . . . . 6
   Appendix A.  Appendix. Revision History . . . . . . . . . . . . . . 6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 7
   Intellectual Property and Copyright Statements  . . . . . . . . . . 9
























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1.  Introduction

   Today, the RFC 3484 [RFC3484] mechanism is widely implemented in
   major OSs.  However, in many sites, the default address-selection
   rules are not appropriate, and cause a communication failure.  PS
   [I-D.ietf-v6ops-addr-select-ps] lists problematic cases that resulted
   from incorrect address selection.

   Though RFC 3484 made the address-selection behavior of a host
   configurable, typical users cannot make use of that because of the
   complexity of the mechanism and lack of knowledge about their network
   topologies.  Therefore, an address-selection autoconfiguration
   mechanism is necessary, especially for unmanaged hosts of typical
   users.

   This document contains requirements for address-selection mechanisms
   that enable hosts to perform appropriate address selection
   automatically.


2.  Requirements of Address Selection

   Address-selection mechanisms have to fulfill the following seven
   requirements.

2.1.  Effectiveness

   The mechanism can modify RFC 3484 default address-selection behavior
   at nodes.  As documented in PS [I-D.ietf-v6ops-addr-select-ps], the
   default rules defined in RFC 3484 do not work properly in some
   environments.  Therefore, the mechanism has to be able to modify
   address-selection behavior of a host.

2.2.  Timing

   Nodes can obtain address selection information when necessary.  If
   nodes need to have address-selection information before performing
   address selection, then the mechanism has to provide a function for
   nodes to obtain necessary information beforehand.  The mechanism
   should not degrade usability.  The mechanism should not enforce long
   address-selection processing time upon users.

2.3.  Dynamic Behavior Update

   Address-selection behavior of nodes can be dynamically updated.  When
   the network structure changes and address-selection behavior has to
   be changed accordingly, a network administrator can modify the
   address-selection behavior of nodes.



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2.4.  Node-Specific Behavior

   The mechanism can support node-specific address-selection behavior.
   Even when multiple nodes are on the same subnet, the mechanism should
   be able to provide a method for the network administrator to make
   nodes behave differently.  For example, each node may have a
   different set of assigned prefixes.  In such a case, the appropriate
   address-selection behavior may be different.

2.5.  Application-Specific Behavior

   The mechanism can support application-specific address-selection
   behavior or combined use with an application-specific address-
   selection mechanism such as address-selection APIs.

2.6.  Multiple Interface

   The mechanism can support those nodes equipped with multiple
   interfaces.  The mechanism has to assume that nodes have multiple
   interfaces and makes address selection of those nodes work
   appropriately.

2.7.  Central Control

   The address selection behavior of nodes can be centrally controlled.
   A site administrator or a service provider could determine or could
   have effect on address-selection behavior at their users' hosts.

2.8.  Next-hop Selection

   The mechanism can control next-hop-selection behavior at hosts or
   cooperate with other routing mechanisms, such as routing protocols
   and RFC 4191 [RFC4191].  If the address-selection mechanism is used
   with a routing mechanism, the two mechanisms have to be able to work
   synchronously.

2.9.  Compatibility with RFC 3493

   The mechanism can allow an application that uses the basic socket
   interface defined in RFC 3493 [RFC3493] to work correctly.  That is,
   with the basic socket interface the application can select an
   appropriate source and destination addresses and can communicate with
   the destination host.  This requirement does not necessarily mean
   that OS protocol stack and socket libraries should not be changed.







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2.10.  Compatibility and Interoperability with RFC 3484

   The mechanism has compatibility with RFC 3484.  Now that RFC 3484 is
   widely implemented, it may be most preferrable that a new address
   selection mechanism does not conflict with the address selection
   mechanisms defined in RFC 3484.

   If the solution mechanism changes or replaces the address selection
   mechanism defined in RFC 3484, interoperability has to be retained.
   That is, a host with the new solution mechanism and a host with the
   mechanism of RFC 3484 have to be interoperable.

2.11.  Security

   The mechanism works without any security problems.  Possible security
   threats are described in Security Considerations section.


3.  Security Considerations

3.1.  List of threats introduced by new address-selection mechanism

   There will be some security incidents when combining these
   requirements described in Section 2 into a protocol.  In particular,
   there are 3 types of threats, "Leakage","Hijacking", and "Denial of
   Services".

   1.  Tapping from malicious nodes to collect the network policy
       information and leak them to unauthorized parties.
   2.  Hijacking of nodes made possible by malicious injection of
       illegitimate policy information: RFC3484 defines both of source
       and destination selection algorithm.  An attacker able to inject
       malicious policy information could redirect packets sent by a
       victim node to an intentionally chosen server that would scan the
       victim node activities to find out exploit code.  Once exploit
       code is found the attacker can take control of the victim node.
   3.  Denial of Service Attack on the ability of nodes to communicate
       in the absence of the address selection policy: An attacker could
       launch a flooding attack on the controller to prevent it to
       deliver the address selection policy information to nodes, thus
       preventing these nodes to appropriately communicate in the
       absence of that information.

3.2.  List of recommendations in which security mechanism should be
      applied

   The source address selection protocol should be afforded security
   services listed below.  It is preferable that these security services



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   are afforded via use of existing protocols(e.g.  IPsec).

   1.  Integrity of the network policy information itself and the
       messages exchanging in the protocol.  This is countermeasure
       against "Leakage", "Hijacking", and "Denial of Services".
   2.  Authentication and authorization of parties involved in the
       protocol.  This is countermeasure against "Leakage" and
       "Hijacking".


4.  IANA Considerations

   This document has no actions for IANA.


5.  References

5.1.  Normative References

   [I-D.ietf-v6ops-addr-select-ps]
              Matsumoto, A., Fujisaki, T., Hiromi, R., and K. Kanayama,
              "Problem Statement of Default Address Selection in Multi-
              prefix Environment:  Operational Issues of RFC3484 Default
              Rules", draft-ietf-v6ops-addr-select-ps-05 (work in
              progress), April 2008.

   [RFC3484]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", RFC 3484, February 2003.

   [RFC3493]  Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.
              Stevens, "Basic Socket Interface Extensions for IPv6",
              RFC 3493, February 2003.

   [RFC4191]  Draves, R. and D. Thaler, "Default Router Preferences and
              More-Specific Routes", RFC 4191, November 2005.

5.2.  Informative References


Appendix A.  Appendix. Revision History

   01:
      Other than policy table distribution approach, the solution
      section included several solutions discussed at 67th IETF meeting.
   02:






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      The description and evaluation of solution approaches were
      separated into a new document called
      draft-arifumi-v6ops-addr-select-sol-00.
   03:
      Security Considerations section was rewritten according to
      comments from SECDIR.
   04:
      A new requirement item "Compatibility with RFC 3493" was added,
      which reflected a comment from Remi Denis-Courmont at the v6ops
      mailing list.
   05:
      A new requirement item "Security" was added.  Security
      Considerations section was rewritten according to comments from
      SECDIR.
   06:
      A new requirement item "Compatibility and Interoperability with
      RFC 3484" was added in response to comments from Tim Polk.


Authors' Addresses

   Arifumi Matsumoto
   NTT PF Lab
   Midori-Cho 3-9-11
   Musashino-shi, Tokyo  180-8585
   Japan

   Phone: +81 422 59 3334
   Email: arifumi@nttv6.net


   Tomohiro Fujisaki
   NTT PF Lab
   Midori-Cho 3-9-11
   Musashino-shi, Tokyo  180-8585
   Japan

   Phone: +81 422 59 7351
   Email: fujisaki@nttv6.net












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   Ruri Hiromi
   Intec Netcore, Inc.
   Shinsuna 1-3-3
   Koto-ku, Tokyo  136-0075
   Japan

   Phone: +81 3 5665 5069
   Email: hiromi@inetcore.com


   Ken-ichi Kanayama
   Intec Netcore, Inc.
   Shinsuna 1-3-3
   Koto-ku, Tokyo  136-0075
   Japan

   Phone: +81 3 5665 5069
   Email: kanayama@inetcore.com

































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