Internet Engineering Task Force (IETF)                           G. Zorn
Request for Comments: 6440                                   Network Zen
Category: Standards Track                                          Q. Wu
ISSN: 2070-1721                                                  Y. Wang
                                                                  Huawei
                                                           December 2011


The EAP Re-authentication Protocol (ERP) Local Domain Name DHCPv6 Option

Abstract

   In order to derive a Domain-Specific Root Key (DSRK) from the
   Extended Master Session Key (EMSK) generated as a side effect of an
   Extensible Authentication Protocol (EAP) method, the EAP peer must
   discover the name of the domain to which it is attached.

   This document specifies a Dynamic Host Configuration Protocol
   Version 6 (DHCPv6) option designed to allow a DHCPv6 server to inform
   clients using the EAP Re-authentication Protocol (ERP) EAP method of
   the name of the local domain for ERP.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6440.

Copyright Notice

   Copyright (c) 2011 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
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   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
      2.1. Standards Language .........................................3
      2.2. Acronyms ...................................................3
   3. Option Format ...................................................3
      3.1. DHCPv6 ERP Local Domain Name Option ........................3
   4. Client Behavior .................................................4
   5. Relay Agent Behavior ............................................4
   6. Security Considerations .........................................4
   7. IANA Considerations .............................................4
   8. References ......................................................5
      8.1. Normative References .......................................5
      8.2. Informative References .....................................5

1.  Introduction

   The EAP Re-authentication Protocol (ERP) [RFC5296] is designed to
   allow faster re-authentication of a mobile device that was previously
   authenticated by means of the Extensible Authentication Protocol
   [RFC3748].  Given that the local root key (e.g., a DSRK, as described
   in RFC 5295 [RFC5295]) is generated using the local domain name
   (LDN), LDN discovery is an important part of re-authentication.  As
   described in RFC 5296 [RFC5296], the LDN to be used in ERP can be
   learned by the mobile device through the ERP exchange or via a lower-
   layer mechanism.  However, no lower-layer mechanisms for LDN
   discovery have yet been defined.

   This document specifies an extension to DHCPv6 for LDN to be used
   in ERP.

2.  Terminology

2.1.  Standards Language

   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].

2.2.  Acronyms

   o  FQDN: Fully Qualified Domain Name

   o  AAA: Authentication, Authorization, and Accounting

   o  DSRK: Domain-Specific Root Key

3.  Option Format

   In DHCPv6-based local domain name discovery, the LDN option is used
   by the DHCPv6 client to obtain the local domain name from the DHCPv6
   server after full EAP authentication has taken place.

   The contents of the ERP Local Domain Name option are intended only
   for use with ERP and do not represent the name of a local domain for
   any other purposes.

3.1.  DHCPv6 ERP Local Domain Name Option

   The format of this 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_ERP_LOCAL_DOMAIN_NAME|         option-length         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | erp-local-domain-name...
   +-+-+-+-+-+-+-+-+-+-+-+-+-

   option code
      OPTION_ERP_LOCAL_DOMAIN_NAME (65)

   option-length
      Length of the erp-local-domain-name field, in octets

   erp-local-domain-name
      This field contains the name of the local ERP domain and MUST be
      encoded as specified in Section 8 of RFC 3315 [RFC3315].  Note
      that this encoding does enable the use of internationalized domain
      names, but only as a set of A-labels [RFC5890].

4.  Client Behavior

   If a DHCPv6 client doesn't know the ERP LDN and requires the DHCPv6
   server to provide the DHCPv6 ERP LDN option, it MUST include an
   Option Request option requesting the DHCPv6 ERP Local Domain Name
   option, as described in Section 22.7 of RFC 3315 [RFC3315].

   When the DHCPv6 client receives an ERP Local Domain Name option with
   the ERP LDN present in it, it MUST verify that the option length is
   no more than 256 octets (the maximum length of a single fully
   qualified domain name (FQDN) allowed by the DNS), and that the local
   domain name is a properly encoded single FQDN, as specified in
   Section 8 of RFC 3315 ("Representation and Use of Domain Names")
   [RFC3315].

5.  Relay Agent Behavior

   If a DHCPv6 relay agent has pre-existing knowledge of the ERP local
   domain name for a client (for example, from a previous AAA exchange),
   it SHOULD include it in an instance of the DHCPv6 ERP Local Domain
   Name option and forward to the DHCPv6 server as a suboption of the
   Relay-Supplied Options option [RFC6422].

6.  Security Considerations

   The communication between the DHCPv6 client and the DHCPv6 server for
   the exchange of local domain name information is security sensitive
   and requires server authentication and integrity protection.  DHCPv6
   security as described in [RFC3315] can be used for this purpose.

7.  IANA Considerations

   IANA has added the name "OPTION_ERP_LOCAL_DOMAIN_NAME" to the
   registry titled "Options Permitted in the Relay-Supplied Options
   Option" maintained at http://www.iana.org/.

   IANA has assigned one new option code to the registry titled "DHCP
   Option Codes" maintained at http://www.iana.org/, referencing this
   document.

8.  References

8.1.  Normative References

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

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

   [RFC5295]  Salowey, J., Dondeti, L., Narayanan, V., and M. Nakhjiri,
              "Specification for the Derivation of Root Keys from an
              Extended Master Session Key (EMSK)", RFC 5295,
              August 2008.

   [RFC5296]  Narayanan, V. and L. Dondeti, "EAP Extensions for EAP
              Re-authentication Protocol (ERP)", RFC 5296, August 2008.

   [RFC6422]  Lemon, T. and Q. Wu, "Relay-Supplied DHCP Options",
              RFC 6422, December 2011.

8.2.  Informative References

   [RFC3748]  Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
              Levkowetz, Ed., "Extensible Authentication Protocol
              (EAP)", RFC 3748, June 2004.

   [RFC5890]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Definitions and Document Framework",
              RFC 5890, August 2010.

Authors' Addresses

   Glen Zorn
   Network Zen
   227/358 Thanon Sanphawut
   Bang Na, Bangkok  10260
   Thailand

   Phone: +66 (0) 87-040-4617
   EMail: glenzorn@gmail.com


   Qin Wu
   Huawei Technologies Co., Ltd.
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Phone: +86-25-56623633
   EMail: sunseawq@huawei.com


   Yungui Wang
   Huawei Technologies Co., Ltd.
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Phone: +86-25-56624545
   EMail: w52006@huawei.com