Network Working Group                                      Myung-Ki Shin
Internet-Draft                                              Yong-Jin Kim
Expires: August 2002                                                ETRI
                                                           February 2002

                      DSTM Ports Option for DHCPv6
              draft-ietf-dhc-dhcpv6-opt-dstm-ports-00.txt


Status of this Memo

     This document is an Internet-Draft and is in full conformance with
     all provisions of Section 10 of RFC2026.

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     This Internet-Draft will expire on August 2002.


Copyright Notice

     Copyright (C) The Internet Society (2002).  All Rights Reserved.


Abstract

     The DSTM Ports Option provide DSTM (Dual Stack Transition
     Mechanism) configuration information to DHCPv6 hosts.


1. Introduction

     This document describes the Ports Option for DHCPv6 [2] that
     provide information for hosts using the "Dual Stack Transition
     Mechanism" (DSTM) [3].






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2. 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 RFC 2119 [1].


3. Terminology

     This document uses terminology specific to IPv6 and DHCPv6 as
     defined in section "Terminology" of the DHCPv6 specification.


4. DSTM Ports Option

     The DSTM Ports option carries a port range that is to be used for
     the associated IPv4-mapped IPv6 address in a DSTM Global IPv4
     Address option.

     The format of the  DSTM Ports option is:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      OPTION_DSTM_PORTS        |          option-length        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |         start port            |          end port             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      option-code:   OPTION_DSTM_PORTS

      option-length: 4

      start port:    The start port number for the associated IPv4-
                     mapped IPv6 address.

      end port:      The end port number for the associated IPv4-
                     mapped IPv6 address.

     A DSTM Ports option MAY be encapsulated in the DSTM Global IPv4
     Address option to specify the port range associted with the IPv4-
     mapped IPv6 address.

     A DSTM Ports option MUST NOT be used except when encapsulated in a
     DSTM Global IPv4 Address option.


5. Appearance of these options

     The DSTM Ports option MUST only appear in the options section of
     the following DHCP messages: Solicit, Advertise, Request, Confirm,
     Renew, Rebind, Decline, Release, Reply.




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     The DSTM Ports option MUST only appear as an encapsulated option in
     a DSTM Global IPv4 Address option.


6. Security Considerations

     The DSTM Ports option may be used by an intruder DHCP server to
     assign an invalid port range to a DHCP client in a denial of
     service attack.

     To avoid this security hazard, a DHCP client MUST use authenticated
     DHCP to confirm that it is exchanging the DSTM options with an
     authorized DHCP server.


7. IANA Considerations

     IANA is requested to assign an option code to this option from the
     option-code space defined in section "DHCP Option" of the DHCPv6
     specification [2].


References


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

[2]  Bound, J., Carney, M., Perkins, C., Lemon, T., Volz, B. and R.
     Droms (ed.), "Dynamic Host Configuration Protocol for IPv6
     (DHCPv6)", draft-ietf-dhc-dhcpv6-23 (work in progress), February
     2002.

[3]  Bound, J., "Dual Stack Transition Mechanism (DSTM)", draft-ietf-
     ngtrans-dstm-06 (work in progress), Feburary 2002.

[4]  Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture",
     RFC 2373, July 1998.

[5]  Bound, J. et al., "DSTM Options for DHCPv6", draft-ietf-dhc-
     dhcpv6-opt-dstm-00.txt, (work in progress), February 2002.



Authors' Addresses

  Myung-Ki Shin
  ETRI PEC
  161 Kajong-Dong, Yusong-Gu, Taejon 305-350, Korea
  Tel : +82 42 860 4847
  Fax : +82 42 861 5404
  E-mail : mkshin@pec.etri.re.kr




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  Yong-Jin Kim
  ETRI PEC
  161 Kajong-Dong, Yusong-Gu, Taejon 305-350, Korea
  Tel : +82 42 860 6564
  Fax : +82 42 861 5404
  E-mail : yjkim@pec.etri.re.kr



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