Lightweight Directory Access Protocol (LDAP): Directory Information Models
RFC 4512

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 14

Network Working Group                                        K. Zeilenga
Request for Comments: 4512                           OpenLDAP Foundation
Obsoletes: 2251, 2252, 2256, 3674                              June 2006
Category: Standards Track

             Lightweight Directory Access Protocol (LDAP):
                      Directory Information Models

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 (2006).

Abstract

   The Lightweight Directory Access Protocol (LDAP) is an Internet
   protocol for accessing distributed directory services that act in
   accordance with X.500 data and service models.  This document
   describes the X.500 Directory Information Models, as used in LDAP.

Zeilenga                    Standards Track                     [Page 1]
RFC 4512                      LDAP Models                      June 2006

Table of Contents

   1. Introduction ....................................................3
      1.1. Relationship to Other LDAP Specifications ..................3
      1.2. Relationship to X.501 ......................................4
      1.3. Conventions ................................................4
      1.4. Common ABNF Productions ....................................4
   2. Model of Directory User Information .............................6
      2.1. The Directory Information Tree .............................7
      2.2. Structure of an Entry ......................................7
      2.3. Naming of Entries ..........................................8
      2.4. Object Classes .............................................9
      2.5. Attribute Descriptions ....................................12
      2.6. Alias Entries .............................................16
   3. Directory Administrative and Operational Information ...........17
      3.1. Subtrees ..................................................17
      3.2. Subentries ................................................18
      3.3. The 'objectClass' attribute ...............................18
      3.4. Operational Attributes ....................................19
   4. Directory Schema ...............................................22
      4.1. Schema Definitions ........................................23
      4.2. Subschema Subentries ......................................32
      4.3. 'extensibleObject' object class ...........................35
      4.4. Subschema Discovery .......................................35
   5. DSA (Server) Informational Model ...............................36
      5.1. Server-Specific Data Requirements .........................36
   6. Other Considerations ...........................................40
      6.1. Preservation of User Information ..........................40
      6.2. Short Names ...............................................41
      6.3. Cache and Shadowing .......................................41
   7. Implementation Guidelines ......................................42
      7.1. Server Guidelines .........................................42
      7.2. Client Guidelines .........................................42
   8. Security Considerations ........................................43
   9. IANA Considerations ............................................43
   10. Acknowledgements ..............................................44
   11. Normative References ..........................................45
   Appendix A. Changes ...............................................47
      A.1. Changes to RFC 2251 .......................................47
      A.2. Changes to RFC 2252 .......................................49
      A.3. Changes to RFC 2256 .......................................50
      A.4. Changes to RFC 3674 .......................................51

Zeilenga                    Standards Track                     [Page 2]
RFC 4512                      LDAP Models                      June 2006

1.  Introduction

   This document discusses the X.500 Directory Information Models
   [X.501], as used by the Lightweight Directory Access Protocol (LDAP)
   [RFC4510].

   The Directory is "a collection of open systems cooperating to provide
   directory services" [X.500].  The information held in the Directory
   is collectively known as the Directory Information Base (DIB).  A
   Directory user, which may be a human or other entity, accesses the
   Directory through a client (or Directory User Agent (DUA)).  The
   client, on behalf of the directory user, interacts with one or more
   servers (or Directory System Agents (DSA)).  A server holds a