Feature Discovery in Lightweight Directory Access Protocol (LDAP)
RFC 3674
Document | Type |
RFC - Proposed Standard
(December 2003; No errata)
Obsoleted by RFC 4512
Was draft-zeilenga-ldap-features (individual in app area)
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Author | Kurt Zeilenga | ||
Last updated | 2018-07-18 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3674 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Ted Hardie | ||
Send notices to | (None) |
Network Working Group K. Zeilenga Request for Comments: 3674 OpenLDAP Foundation Category: Standards Track December 2003 Feature Discovery in Lightweight Directory Access Protocol (LDAP) Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. 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. 1. Background and Intended Use The Lightweight Directory Access Protocol (LDAP) [RFC3377] is an extensible protocol with numerous elective features. LDAP provides mechanisms for a client to discover supported protocol versions, controls, extended operations, Simple Authentication and Security Layer (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 elective features supported by a server. For example, this mechanism could be used by a client to discover whether or not the server supports requests for all operational attributes, e.g., "+" [RFC3673]. As another example, this mechanism could be used to discover absolute true, e.g., "(&)" and false, e.g., "(|)", search filters [T-F] support. This document extends the LDAP Protocol Mechanism registry [RFC3383] to support registration of values of the supportedFeatures attribute. This registry is managed by the Internet Assigned Numbers Authority (IANA). Zeilenga Standards Track [Page 1] RFC 3674 Feature Discovery in LDAP December 2003 Schema definitions are provided using LDAP 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 elective 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. A client MUST ignore values it doesn't recognize as they refer to elective features it doesn't implement. Features associated with Standard Track protocol mechanisms MUST be registered. Features associated with other protocol mechanisms SHOULD be registered. Procedures for registering protocol mechanisms are described in BCP 64 [RFC3383]. The word "Feature" should be placed in the usage field of the submitted LDAP Protocol Mechanism template. 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. Zeilenga Standards Track [Page 2] RFC 3674 Feature Discovery in LDAP December 2003 4. IANA Considerations 4.1. Registration of Features as Protocol Mechanisms Future specifications detailing LDAP features are to register each feature as a LDAP Protocol Mechanism per guidance given in BCP 64 [RFC3383]. A usage of "Feature" in a Protocol Mechanism registration template indicates that the value to be registered is associated with an LDAP feature. 4.2. Registration of the supportedFeatures descriptor The IANA has registered the LDAP 'supportedFeatures' descriptor. The following registration template is suggested:Show full document text