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Versions: 00 01 02 03 04 RFC 2489

Network Working Group                                           R. Droms
INTERNET-DRAFT                                       Bucknell University
Obsoletes: draft-ietf-dhc-new-options-03.txt                October 1998
                                                      Expires April 1999


                Procedure for Defining New DHCP Options
                  <draft-ietf-dhc-new-options-04.txt>

Status of this memo

   This document is an Internet-Draft. Internet-Drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas,
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Abstract

   The Dynamic Host Configuration Protocol (DHCP) provides a framework
   for passing configuration information to hosts on a TCP/IP network.
   Configuration parameters and other control information are carried in
   tagged data items that are stored in the 'options' field of the DHCP
   message.  The data items themselves are also called "options."

   New DHCP options may be defined after the publication of the DHCP
   specification to accommodate requirements for conveyance of new
   configuration parameters.  This document describes the procedure for
   defining new DHCP options.

Introduction

   The Dynamic Host Configuration Protocol (DHCP) [1] provides a
   framework for passing configuration information to hosts on a TCP/IP
   network.  Configuration parameters and other control information are
   carried in tagged data items that are stored in the 'options' field
   of the DHCP message.  The data items themselves are also called
   "options." [2]



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DRAFT           Procedure for Defining New DHCP Options     October 1998


   This document describes the procedure for defining new DHCP options.
   The procedure will guarantee that:

   * allocation of new option numbers is coordinated from a single
     authority,
   * new options are reviewed for technical correctness and
     appropriateness, and
   * documentation for new options is complete and published.

   As indicated in "Guidelines for Writing an IANA Considerations
   Section in RFCs" (see references), IANA acts as a central authority
   for assignment of numbers such as DHCP option codes.  The new
   procedure outlined in this document will provide guidance to IANA in
   the assignment of new option codes.

Overview and background

   The procedure described in this document modifies and clarifies the
   procedure for defining new options in RFC 2131 [2].  The primary
   modification is to the time at which a new DHCP option is assigned an
   option number.  In the procedure described in this document, the
   option number is not assigned until specification for the option is
   about to be published as an RFC.

   Since the publication of RFC 2132, the option number space for
   publically defined DHCP options (1-127) has almost been exhausted.
   Many of the defined option numbers have not been followed up with
   Internet Drafts submitted to the DHC WG.  There has been a lack of
   specific guidance to IANA from the DHC WG as to the assignment of
   DHCP option numbers

   The procedure as specified in RFC 2132 does not clearly state that
   new options are to be reviewed individually for technical
   correctness, appropriateness and complete documentation.  RFC 2132
   also does not require that new options are to be submitted to the
   IESG for review, and that the author of the option specification is
   responsible for bringing new options to the attention of the IESG.
   Finally, RFC 2132 does not make clear that newly defined options are
   not to be incorporated into products, included in other
   specifications or otherwise used until the specification for the
   option is published as an RFC.

   In the future, new DHCP option codes will be assigned by IETF
   consensus.  New DHCP options will be documented in RFCs approved by
   the IESG, and the codes for those options will be assigned at the
   time the relevant RFCs are published.  Typically, the IESG will seek
   input on prospective assignments from appropriate sources (e.g., a
   relevant Working Group if one exists).  Groups of related options may



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   be combined  into a single specification and reviewed as a set by the
   IESG.  Prior to assignment of an option code, it is not appropriate
   to incorporate new options into products, include the specification
   in other documents or otherwise make use of the new options.

   The DHCP option number space (1-254) is split into two parts.  The
   site-specific options (128-254) are defined as "Private Use" and
   require no review by the DHC WG.  The public options (1-127) are
   defined as "Specification Required" and new options must be reviewed
   prior to assignment of an option number by IANA.  The details of the
   review process are given in the following section of this document.


Procedure

   The author of a new DHCP option will follow these steps to obtain
   approval for the option and publication of the specification of the
   option as an RFC:

   1. The author devises the new option.
   2. The author documents the new option, leaving the option code as
      "To Be Determined" (TBD), as an Internet Draft.

      The requirement that the new option be documented as an Internet
      Draft is a matter of expediency.  In theory, the new option could
      be documented on the back of an envelope for submission; as a
      practical matter, the specification will eventually become an
      Internet Draft as part of the review process.

   3. The author submits the Internet Draft for review by the IESG.
      Preferably, the author will submit the Internet Draft to the DHC
      Working Group, but the author may choose to submit the Internet
      Draft directly to the IESG.

      Note that simply publishing the new option as an Internet Draft
      does not automatically bring the option to the attention of the
      IESG.  The author of the new option must explicitly forward a
      request for action on the new option to the DHC WG or the IESG.

   4. The specification of the new option is reviewed by the IESG.  The
      specification is reviewed by the DHC WG (if it exists) or by the
      IETF.  If the option is accepted for inclusion in the DHCP
      specification, the specification of the option is published as an
      RFC.  It may be published as either a standards-track or a non-
      standards-track RFC.

   5. At the time of publication as an RFC, IANA assigns a DHCP option
      number to the new option.



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DRAFT           Procedure for Defining New DHCP Options     October 1998


References

[1] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, Bucknell
    University, March 1997.

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

[3] Droms, R. and K. Fong, "NetWare/IP Domain Name and Information", RFC
    2142, November 1997.

    Note: This document was written after consideration of information
    found in "Guidelines for Writing an IANA Considerations Section in
    RFCs" <draft-iesg-iana-considerations-06.txt>, by T. Narten and H.
    T. Alvestrand, which is a work in progress.



Security Considerations

   Information that creates or updates an option number assignment needs
   to be authenticated.

   An analysis of security issues is required for all newly defined DHCP
   options.  The description of security issues in the specification of
   new options must be as accurate as possible.  The specification for a
   new option may reference the "Security Considerations" section in the
   DHCP specification [1]; e.g. (from "NetWare/IP Domain Name and
   Information" [3]):

      DHCP currently provides no authentication or security mechanisms.
      Potential exposures to attack are discussed in section 7 of the
      DHCP protocol specification [RFC 2131].

Author's Address

   Ralph Droms
   Computer Science Department
   323 Dana Engineering
   Bucknell University
   Lewisburg, PA 17837

   Phone: (717) 524-1145
   EMail: droms@bucknell.edu

Expiration

   This document will expire on March 31, 1999.



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DRAFT           Procedure for Defining New DHCP Options     October 1998


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Droms                                                           [Page 5]


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