INTERNET-DRAFT Kurt D. Zeilenga
Intended Category: Standard Track OpenLDAP Foundation
Expires: 20 May 2002 20 November 2001
Feature Discovery in LDAP
<draft-zeilenga-ldap-features-02.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>.
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Copyright 2001, 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 discovery 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'', and ``MAY'' 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
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believed to introduce any new security risk to LDAP.
4. Acknowledgment
This document is based upon input from the IETF LDAPext working group.
5. Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
<Kurt@OpenLDAP.org>
6. Normative References
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", 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.
Full Copyright
Copyright 2001, 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
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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.
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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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