





INTERNET-DRAFT                                      Kurt D. Zeilenga
Intended Category: Standard Track                   OpenLDAP Foundation
Expires in six months                               17 May 2002


                        Feature Discovery in LDAP
                  <draft-zeilenga-ldap-features-03.txt>


Status of this Memo

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

  This document is intended to be, after appropriate review and
  revision, submitted to the RFC Editor as an Standard Track document.
  Distribution of this memo is unlimited.  Technical discussion of this
  document will take place on the IETF LDAP Extension Working Group
  mailing list <ietf-ldapext@netscape.com>.  Please send editorial
  comments directly to the author <Kurt@OpenLDAP.org>.

  Internet-Drafts are working documents of the Internet Engineering Task
  Force (IETF), its areas, and its working groups.  Note that other
  groups may also distribute working documents as Internet-Drafts.
  Internet-Drafts are draft documents valid for a maximum of six months
  and may be updated, replaced, or obsoleted by other documents at any
  time.  It is inappropriate to use Internet-Drafts as reference
  material or to cite them other than as ``work in progress.''

  The list of current Internet-Drafts can be accessed at
  <http://www.ietf.org/ietf/1id-abstracts.txt>. The list of
  Internet-Draft Shadow Directories can be accessed at
  <http://www.ietf.org/shadow.html>.

  Copyright 2002, The Internet Society.  All Rights Reserved.

  Please see the Copyright section near the end of this document for
  more information.


Abstract

  The Lightweight Directory Access Protocol (LDAP) is an extensible
  protocol with numerous elective features.  This document introduces a
  general mechanism for discovery of elective features and extensions
  which cannot be discovered using existing mechanisms.





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1. Background and Intended Use

  LDAP [RFC2251] is an extensible protocol with numerous elective
  features.  LDAP provides mechanisms for a client to discover supported
  protocol versions, controls, extended operations, SASL mechanisms, and
  subschema information.  However, these mechanisms are not designed to
  support general feature discovery.

  This document describes a simple, general-purpose mechanism which
  clients may use to discover the set of features supported by a server.

  Schema definitions are provided using LDAPv3 description formats
  [RFC2252].  Definitions provided here are formatted (line wrapped) for
  readability.

  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 BCP 14 [RFC2119].


2. Discovery of supported features

  Each feature whose support may be discovered SHALL be identified by an
  Object Identifier (OID).  A server advertises its support for a given
  feature by providing the OID associated with the feature as a value of
  the supportedFeatures attribute held in the root DSE.  A client may
  examine the values of this attribute to determine if a particular
  feature is supported by the server.

  The supportedFeatures attribute type is described as follows:

      ( 1.3.6.1.4.1.4203.1.3.5
        NAME 'supportedFeatures'
        DESC 'features supported by the server'
        EQUALITY objectIdentifierMatch
        SYNTAX 1.3.6.1.4.1.1466.115.121.1.38
        USAGE dSAOperation )

  Servers MUST be capable of recognizing this attribute type by the name
  'supportedFeatures'.  Servers MAY recognize the attribute type by
  other names.


3. Security Considerations

  As rogue clients can discover features of a server by other means
  (such as by trial and error), this feature discovery mechanism is not
  believed to introduce any new security risk to LDAP.



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4. IANA Considerations

  It is requested that IANA register the LDAP 'supportedFeatures'
  descriptor used in this document per the following registration
  template:

      Subject: Request for LDAP Descriptor Registration
      Descriptor (short name): supportedFeatures
      Object Identifier: 1.3.6.1.4.1.4203.1.3.5
      Person & email address to contact for further information:
          Kurt Zeilenga <kurt@OpenLDAP.org>
      Usage: Attribute Type
      Specification: RFCXXXX
      Author/Change Controller: IESG


  This OID was assigned [ASSIGN] by OpenLDAP Foundation under its IANA
  assigned private enterprise allocation [PRIVATE] for use in this
  specification.


5. Acknowledgment

  This document is based upon input from the IETF LDAPext working group.


6. Author's Address

  Kurt D. Zeilenga
  OpenLDAP Foundation
  <Kurt@OpenLDAP.org>


7. Normative References

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

  [RFC2251] M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access
            Protocol (v3)", RFC 2251, December 1997.

  [RFC2252] M. Wahl, A. Coulbeck, T. Howes, S. Kille, "Lightweight
            Directory Access Protocol (v3):  Attribute Syntax
            Definitions", RFC 2252, December 1997.


8. Informative References




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Full Copyright

  Copyright 2002, The Internet Society.  All Rights Reserved.

  This document and translations of it may be copied and furnished to
  others, and derivative works that comment on or otherwise explain it
  or assist in its implementation may be prepared, copied, published and
  distributed, in whole or in part, without restriction of any kind,
  provided that the above copyright notice and this paragraph are
  included on all such copies and derivative works.  However, this
  document itself may not be modified in any way, such as by removing
  the copyright notice or references to the Internet Society or other
  Internet organizations, except as needed for the  purpose of
  developing Internet standards in which case the procedures for
  copyrights defined in the Internet Standards process must be followed,
  or as required to translate it into languages other than English.

  The limited permissions granted above are perpetual and will not be
  revoked by the Internet Society or its successors or assigns.

  This document and the information contained herein is provided on an
  "AS IS" basis and THE AUTHORS, THE INTERNET SOCIETY, AND THE INTERNET
  ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
  INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
  INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
  WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

























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