Lightweight Directory Access Protocol (v3): Attribute Syntax Definitions
RFC 2252

Document Type RFC - Proposed Standard (December 1997; Errata)
Updated by RFC 3377
Authors Andy Coulbeck  , Mark Wahl  , Steve Kille  , Tim Howes 
Last updated 2020-01-21
Stream Internent Engineering Task Force (IETF)
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IESG IESG state RFC 2252 (Proposed Standard)
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Network Working Group                                            M. Wahl
Request for Comments: 2252                           Critical Angle Inc.
Category: Standards Track                                    A. Coulbeck
                                                              Isode Inc.
                                                                T. Howes
                                           Netscape Communications Corp.
                                                                S. Kille
                                                           Isode Limited
                                                           December 1997

              Lightweight Directory Access Protocol (v3):
                      Attribute Syntax Definitions

1. 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 (1997).  All Rights Reserved.


   This document describes a directory access protocol that provides
   both read and update access.  Update access requires secure
   authentication, but this document does not mandate implementation of
   any satisfactory authentication mechanisms.

   In accordance with RFC 2026, section 4.4.1, this specification is
   being approved by IESG as a Proposed Standard despite this
   limitation, for the following reasons:

   a. to encourage implementation and interoperability testing of
      these protocols (with or without update access) before they
      are deployed, and

   b. to encourage deployment and use of these protocols in read-only
      applications.  (e.g. applications where LDAPv3 is used as
      a query language for directories which are updated by some
      secure mechanism other than LDAP), and

Wahl, et. al.               Standards Track                     [Page 1]
RFC 2252                   LADPv3 Attributes               December 1997

   c. to avoid delaying the advancement and deployment of other Internet
      standards-track protocols which require the ability to query, but
      not update, LDAPv3 directory servers.

   Readers are hereby warned that until mandatory authentication
   mechanisms are standardized, clients and servers written according to
   this specification which make use of update functionality are

   Implementors are hereby discouraged from deploying LDAPv3 clients or
   servers which implement the update functionality, until a Proposed
   Standard for mandatory authentication in LDAPv3 has been approved and
   published as an RFC.

2. Abstract

   The Lightweight Directory Access Protocol (LDAP) [1] requires that
   the contents of AttributeValue fields in protocol elements be octet
   strings.  This document defines a set of syntaxes for LDAPv3, and the
   rules by which attribute values of these syntaxes are represented as
   octet strings for transmission in the LDAP protocol.  The syntaxes
   defined in this document are referenced by this and other documents
   that define attribute types.  This document also defines the set of
   attribute types which LDAP servers should support.

3. Overview

   This document defines the framework for developing schemas for
   directories accessible via the Lightweight Directory Access Protocol.

   Schema is the collection of attribute type definitions, object class
   definitions and other information which a server uses to determine
   how to match a filter or attribute value assertion (in a compare
   operation) against the attributes of an entry, and whether to permit
   add and modify operations.

   Section 4 states the general requirements and notations for attribute
   types, object classes, syntax and matching rule definitions.

   Section 5 lists attributes, section 6 syntaxes and section 7 object

   Additional documents define schemas for representing real-world
   objects as directory entries.

Wahl, et. al.               Standards Track                     [Page 2]
RFC 2252                   LADPv3 Attributes               December 1997

4. General Issues

   This document describes encodings used in an Internet protocol.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119 [4].

   Attribute Type and Object Class definitions are written in a string
   representation of the AttributeTypeDescription and
   ObjectClassDescription data types defined in X.501(93) [3].
   Implementors are strongly advised to first read the description of
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