DHC Working Group                                               S. Jiang
Internet-Draft                              Huawei Technologies Co., Ltd
Intended status: Standards Track                                 G. Chen
Expires: March 15, 2015                                     China Mobile
                                                             S. Krishnan
                                                                R. Asati
                                                     Cisco Systems, Inc.
                                                      September 11, 2014

     Registering Self-generated IPv6 Addresses in DNS using DHCPv6


   In networks that are centrally managed, self-generated addresses
   cause some traceability issues due to their decentralized nature.
   One of the most important issues in this regard is the inability to
   register such addresses in DNS.  This document defines a mechanism to
   register self-generated and statically configured addresses in DNS
   through a DHCPv6 server.

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
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 15, 2015.

Copyright Notice

   Copyright (c) 2014 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

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   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Solution Overview . . . . . . . . . . . . . . . . . . . . . .   3
   4.  DHCPv6 ADDR-REGISTRATION-REQUEST Message  . . . . . . . . . .   4
   5.  DHCPv6 Address Registration Procedure . . . . . . . . . . . .   5
     5.1.  DHCPv6 Address Registration Request . . . . . . . . . . .   6
     5.2.  Registration Expiry and Refresh . . . . . . . . . . . . .   6
     5.3.  Acknowledging Registration and Retransmission . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   In several common network scenarios, IPv6 addresses are self-
   generated by the end-hosts by appending a self-generated interface
   identifier to a network-specified prefix.  Examples of self-generated
   addresses include those created using IPv6 Stateless Address
   Configuration [RFC4862] , temporary addresses [RFC4941] and
   Cryptographically Generated Addresses (CGA) [RFC3972] etc.  In
   several tightly controlled networks, hosts with self-generated
   addresses may face some limitations.  One such limitation is related
   to the inability of nodes with self-generated addresses to register
   their IPv6-address-to-FQDN bindings in DNS.  This is related to the
   fact that, in such networks, only certain nodes (e.g.  The DHCPv6
   server) are allowed to update these bindings in order to prevent end-
   hosts from registering arbitrary addresses for their FQDNs or
   associating their addresses with arbitrary domain names.  The
   administrators may not want to distribute the address of
   authoritative name-server.  Also, there is no way to propagate the
   address of authoritative name server by any protocols.  It is
   preferred that the address registration server, which is under the
   same management with the authoritative name-server, to know the
   address of the authoritative name-server and make registration
   requests on behalf of clients.  It is preferred by administrators to

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   establish and manage one trust relationship between a single DHCPv6
   (address registration) server and the DNS authoritative name-server,
   rather than to distribute and manage trust relationships between many
   clients and the DNS authoritative name-server.

   For nodes that obtain their addresses through DHCPv6, a solution has
   been specified in [RFC4704].  The solution works by including a
   Client FQDN option in the SOLICIT, REQUEST, RENEW or REBIND messages
   during the process of acquiring an address through DHCPv6.  This
   document provides an analogous mechanism to register self-generated
   addresses in DNS.

   A new ADDR-REGISTRATION-REQUEST DHCPv6 message type is defined to
   initiate the address registration request, and two new Status codes
   are defined to indicate registration errors on the server side.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].

   Certificate  In this document, the term "Certificate" is all referred
      to public key certificate.

3.  Solution Overview

   After successfully assigning a self-generated IPv6 address on one of
   its interfaces, an end-host implementing this specification SHOULD
   send an ADDR-REGISTRATION-REQUEST message to a DHCPv6 address
   registration server.  After receiving the address registration
   request, the DHCPv6 server registers the IPv6 address to FQDN binding
   towards a configured DNS server.  An acknowledgement MUST be sent
   back to the end host to indicate whether or not the registration
   operation succeeded.

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          +----+   +-----------+                  +---------------+
          |Host|   |Edge router|                  |Addr-Reg Server|
          +----+   +-----------+                  +---------------+
            |   SLAAC   |                                 |
            |<--------->|                                 |
            |           |                                 |
            |           |    ADDR-REGISTRATION-REQUEST    |
            |           |                                 |Register
            |           |                                 |address
            |           |         Acknowledgment          |in DNS

                 Figure 1: Address Registration Procedure

   Furthermore, the registration server MAY apply certain filter/accept
   criteria for the address registration requests, particularly for the
   client chosen domain names.

   It is RECOMMENDED to only set up one address registration server
   within an administration domain, although there may be multiple
   DHCPv6 servers.  While using multiple address registration servers
   does potentially increase the load on DNS, because of how [RFC4703]
   and [RFC4704] work, this should NOT be an issue - the servers should
   work correctly in updating DNS (either adding or removing the
   entries).  The broken part with multiple servers is the 'extension'
   of the registration.  If there are two address registration servers
   and both receive the initial registration and (correctly) update DNS,
   the problem comes when the client extends this but one of the servers
   does not receive this extension.  Then, the server that missed the
   extension removes the entry prematurely (i.e., when it expired


   The DHCPv6 client sends an ADDR-REGISTRATION-REQUEST message to a
   server to request an address to be registered in the DNS.  The format
   of the ADDR-REGISTRATION-REQUEST message is described as follows:

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      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
     |    msg-type   |               transaction-id                  |
     |                                                               |
     .                            options                            .
     .                           (variable)                          .
     |                                                               |
      msg-type             Identifies the DHCPv6 message type;
                           Set to ADDR-REGISTRATION-REQUEST (TBA1).

      transaction-id       The transaction ID for this message exchange.

      options              Options carried in this message.

                 DHCPv6 ADDR-REGISTRATION-REQUEST message

   The ADDR-REGISTRATION-REQUEST message MUST NOT contain server-
   identifier option and MUST contain the IA Address option and the
   DHCPv6 FQDN option [RFC4704].  The ADDR-REGISTRATION-REQUEST message
   is dedicated for clients to initiate an address registration request
   toward an address registration server.  Consequently, clients MUST
   NOT put any Option Request Option(s) in the ADDR-REGISTRATION-REQUEST

   Clients MUST discard any received ADDR-REGISTRATION-REQUEST messages.

   Servers MUST discard any ADDR-REGISTRATION-REQUEST messages that meet
   any of the following conditions:

   o  the message does not include a Client Identifier option;

   o  the message includes a Server Identifier option;

   o  the message does not include at least one IA Address option;

   o  the message does not include FQDN option (or include multiple FQDN

   o  the message includes an Option Request Option.

5.  DHCPv6 Address Registration Procedure

   The DHCPv6 protocol is used as the address registration protocol when
   a DHCPv6 server performs the role of an address registration server.
   The DHCPv6 IA Address option [RFC3315] and the DHCPv6 FQDN option

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   [RFC4704] are adopted in order to fulfill the address registration

5.1.  DHCPv6 Address Registration Request

   The end-host sends a DHCPv6 ADDR-REGISTRATION-REQUEST message to the
   address registration server to the All_DHCP_Relay_Agents_and_Servers
   multicast address (ff02::1:2).

   The end-host MUST include a Client Identifier option in the ADDR-
   REGISTRATION-REQUEST message to identify itself to the server.  The
   DHCPv6 ADDR-REGISTRATION-REQUEST message MUST contain at least one IA
   Address option and exactly one FQDN option.  The valid-lifetime field
   of the IA Address option MUST be set to the period for which the
   client would like to register the binding in DNS.

   After receiving this ADDR-REGISTRATION-REQUEST message, the address
   registration server MUST register the binding between the provided
   FQDN and address(es) in DNS.  If the DHCPv6 server does not support
   address registration function, it MUST sliently drop the message.

5.2.  Registration Expiry and Refresh

   For every successful binding registration, the address registration
   server MUST record the IPv6-address-to-FQDN bindings and associated
   valid-lifetimes in its storage.

   The address registration client MUST refresh the registration before
   it expires (i.e. before the valid-lifetime of the IA address elapses)
   by sending a new ADDR-REGISTRATION-REQUEST to the address
   registration server.  If the address registration server does not
   receive such a refresh after the valid-lifetime has passed, it SHOULD
   remove the IPv6-address-to-FQDN bindings in DNS, also the local

   It is RECOMMENDED that clients initiate a refresh at about 85% of the
   valid-lifetime.  Because RAs may periodically 'reset' the valid-
   lifetime, the refresh timer MUST be independently maintained from the
   address valid-lifetime.  Clients SHOULD set a refresh timer to 85% of
   the valid-lifetime when they complete a registration operation and
   only update this timer if 85% of any updated valid-lifetime would be
   sooner than the timer.

5.3.  Acknowledging Registration and Retransmission

   After an address registration server accepts an address registration
   request, it MUST send a Reply message as the response to the client.
   The acceptence reply only means that the server has taken

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   responsiblity to registry for the client.  It may not have actually
   completed the update yet.  The server is responsible to register all
   the addresses in DNS.  The server generates a Reply message and
   includes a Status Code option with value Success, a Server Identifier
   option with the server's DUID, and a Client Identifier option with
   the client's DUID.

   If there is no reply received within some interval, the client SHOULD
   retransmits the message according to section 14 of [RFC3315], using
   the following parameters:




   o  MRD 0

   The below presents a table of values used to describe the message
   transmission behavior of clients and servers:

    Parameter       Default  Description
   ADDR_REG_TIMEOUT  1  secs  Initial Addr Registration Request timeout
   ADDR_REG_MAX_RT   60 secs  Max Addr Registration Request timeout value
   ADDR_REG_MAX_RC   5        Max Request retry attempts

   For each IA Address option in the ADDR-REGISTRATION-REQUEST message
   for which the server does not accept its associated registration
   request, the server adds an IA Address option with the associated
   IPv6 address, and includes a Status Code option with the value
   RegistrationDenied (TBA2) in the IA Address option.  No other options
   are included in the IA Address option.

   Upon receiving a RegistrationDenied error status code, the client MAY
   also resend the message following normal retransmission routines
   defined in [RFC3315] with above parameters.  The client MUST wait out
   the retransmission time before retrying.

6.  Security Considerations

   An attacker may attempt to register large number of addresses in
   quick succession in order to overwhelm the address registration
   server.  These attacks may be prevented generic DHCPv6 protection by
   using the AUTH option [RFC3315] or Secure DHCPv6

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7.  IANA Considerations

   This document defines a new DHCPv6 message, the ADDR-REGISTRATION-
   REQUEST message (TBA1) described in Section 4, that requires an
   allocation out of the registry of Message Types defined at

      Value          Description           Reference
      TBA1   ADDR-REGISTRATION-REQUEST    this document

   This document defines a new DHCPv6 Status code, the
   RegistrationDenied (TBA2) described in Section 5, that requires an
   allocation out of the registry of Status Codes defined at

      Code            Name                 Reference
      TBA2    RegistrationDenied          this document

8.  Acknowledgements

   The authors would like to thank Ralph Droms, Ted Lemon, Bernie Volz,
   Sten Carlsen, Erik Kline, Lorenzo Colitti, Joel Jaeggli, Sten
   Carlsen, Mark Smith, Marcin Siodelski, Darpan Malhotra, Tomek
   Mrugalski, Jinmei Tatuya and other members of dhc and v6ops working
   groups for their valuable comments.

9.  References

9.1.  Normative References

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

   [RFC2136]  Vixie, P., Thomson, S., Rekhter, Y., and J. Bound,
              "Dynamic Updates in the Domain Name System (DNS UPDATE)",
              RFC 2136, April 1997.

   [RFC3315]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
              and M. Carney, "Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", RFC 3315, July 2003.

   [RFC3972]  Aura, T., "Cryptographically Generated Addresses (CGA)",
              RFC 3972, March 2005.

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   [RFC4703]  Stapp, M. and B. Volz, "Resolution of Fully Qualified
              Domain Name (FQDN) Conflicts among Dynamic Host
              Configuration Protocol (DHCP) Clients", RFC 4703, October

   [RFC4704]  Volz, B., "The Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6) Client Fully Qualified Domain Name (FQDN)
              Option", RFC 4704, October 2006.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862, September 2007.

   [RFC4941]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", RFC 4941, September 2007.

9.2.  Informative References

              Jiang, S., Shen, S., Zhang, D., and T. Jinmei, "Secure
              DHCPv6 with Public Key", draft-ietf-dhc-sedhcpv6-03 (work
              in progress), June 2014.

Authors' Addresses

   Sheng Jiang
   Huawei Technologies Co., Ltd
   Q14, Huawei Campus
   No.156 Beiqing Road
   Hai-Dian District, Beijing 100095
   P.R. China

   Email: jiangsheng@huawei.com

   Gang Chen
   China Mobile
   53A, Xibianmennei Ave., Xuanwu District, Beijing
   P.R. China

   Phone: 86-13910710674
   Email: phdgang@gmail.com

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   Suresh Krishnan
   8400 Decarie Blvd.
   Town of Mount Royal, QC

   Phone: +1 514 345 7900 x42871
   Email: suresh.krishnan@ericsson.com

   Rajiv Asati
   Cisco Systems, Inc.
   7025 Kit Creek road
   Research Triangle Park, NC  27709-4987

   Email: rajiva@cisco.com

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