Network Working Group                                            B. Volz
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                           July 07, 2008
Expires: January 8, 2009


                     DHCPv4 Vendor-specific Message
             <draft-volz-dhc-dhcpv4-vendor-message-00.txt>

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Abstract

   This document requests a vendor-specific DHCPv4 message assignment.
   This message can be used for vendor specific and experimental
   purposes.












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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Vendor-specific Message . . . . . . . . . . . . . . . . . . . . 3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 6
   Intellectual Property and Copyright Statements  . . . . . . . . . . 7







































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1.  Introduction

   The DHCPv4 [RFC2131] protocol specifies a mechanism for the
   assignment of addresses and configuration information to nodes.  The
   protocol provides for 256 possible message codes, of which a small
   number are assigned ([DHCPv4Params]).  Each of the assigned message
   codes have specific purposes.  New message codes are assigned through
   IETF Standards Action.

   There may be a need for vendors of DHCPv4 clients, relay agents, or
   servers to experiment with new capabilities that require new messages
   to be exchanged between these elements.  Thus, this document defines
   the format for and requests that a new message code be reserved for
   vendor-specific and experimental purposes.


2.  Terminology

   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].


3.  Vendor-specific Message

   The vendor-specific message may be exchanged between clients, relay
   agents, and/or servers and allows multiple vendors to make use of the
   message for completely different and independent purposes.

   Clients and servers MAY chose to support this message; those that do
   not, MUST discard the message.  Relay agents SHOULD relay these
   messages as they would other DHCPv4 messages unless the relay agent
   understands the specific message and knows that the message was
   directed at it.

   Applications using these messages MUST NOT assume that all DHCPv4
   clients, relay agents, and servers support them and MUST use good
   networking practices when transmitting and retransmitting these
   messages.  For some applications, it may be appropriate to use
   Vendor-Identifying Vendor Options [RFC3925] in a standard DHCPv4
   exchange to negotiate whether the end-points support the vendor-
   specific message.

   A vendor-specifc message is constructed by placing the Vendor-
   Specific Message number (254) into the DHCP Message Type option
   [RFC2132] and including the Vendor Message Option defined below.  A
   Vendor-Specific Message that does not contain the Vendor Message
   Option MUST be ignored.  A Vendor Message Option in a DHCPv4 message



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   other than the Vendor-Specific Message MUST be ignored.

   The format of the Vendor Message Option is shown below:


                           1 1 1 1 1 1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  option-code  |  option-len   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       enterprise-number       |
      |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      /      vendor-message-data      /
      ~            ...                ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


      option-code         OPTION_VENDOR_MESSAGE (TBD)

      option-len          4 plus the length of the vendor-message-data.

      enterprise-number   The vendor's 32-bit Enterprise Number as
                          registered with [EID], in network octet order.

      vendor-message-data Vendor specific data (of length option-len - 4
                          octets).

   The contents and format of the vendor-message-data field is up to the
   vendor.

   Clients, relay agents, and/or servers supporting the Vendor Message
   Option MUST support [RFC3396].

   Note: Vendor-Identifying Vendor Options [RFC3925] are not used to
   convey the vendor identification (enterprise-number) for the vendor-
   specific message as the message may contain instances of those
   options for other reasons.


4.  Security Considerations

   The Security Considerations of [RFC2131] apply.

   This new message does potentially open up new avenues of attacking
   clients, relay agents, or servers.  The exact nature of these attacks
   will depend on what functions and capabilities the message exposes
   and are thus not possible to describe in this document.  Clients and



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   servers that have no use for these messages SHOULD discard them and
   thus the threat is no different than before this message was
   assigned.

   Vendors using this new message should use the DHCPv4 security
   mechanisms (such as [RFC3118] as appropriate) and carefully consider
   the security implications of the functions and capabilities exposed.


5.  IANA Considerations

   IANA is requested to assign DHCPv4 Message type 254 to the Vendor-
   specific Message in the registry maintained in [DHCPv4Params]:

      254 VENDOR-SPECIFIC

   IANA is requested to assign a DHCPv4 option number to the Vendor
   Message Option in the registry maintained in [DHCPv4Params]:

      TBD OPTION_VENDOR_MESSAGE


6.  References

6.1.  Normative References

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

   [RFC2131]  Droms, R., "Dynamic Host Configuration Protocol",
              RFC 2131, March 1997.

   [EID]      IANA, "Private Enterprise Numbers.
              http://www.iana.org/assignments/enterprise-numbers".

6.2.  Informative References

   [RFC2132]  Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
              Extensions", RFC 2132, March 1997.

   [RFC3118]  Droms, R. and W. Arbaugh, "Authentication for DHCP
              Messages", RFC 3118, June 2001.

   [RFC3396]  Lemon, T. and S. Cheshire, "Encoding Long Options in the
              Dynamic Host Configuration Protocol (DHCPv4)", RFC 3396,
              November 2002.

   [RFC3925]  Littlefield, J., "Vendor-Identifying Vendor Options for



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              Dynamic Host Configuration Protocol version 4 (DHCPv4)",
              RFC 3925, October 2004.

   [DHCPv4Params]
              IANA, "Dynamic Host Configuration Protocol (DHCP) and
              Bootstrap Protocol (BOOTP) Parameters.
              http://www.iana.org/assignments/bootp-dhcp-parameters".


Author's Address

   Bernard Volz
   Cisco Systems, Inc.
   1414 Massachusetts Ave.
   Boxborough, MA  01719
   USA

   Phone: +1 978 936 0000
   Email: volz@cisco.com
































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