RFC5020

Network Working Group K. Zeilenga Request for Comments: 5020 Isode Limited Category: Standards Track August 2007

   The Lightweight Directory Access Protocol (LDAP) entryDN
                     Operational Attribute

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 IETF Trust (2007).

Abstract

This document describes the Lightweight Directory Access Protocol (LDAP) / X.500 'entryDN' operational attribute. The attribute provides a copy of the entry's distinguished name for use in attribute value assertions.

Background and Intended Use

In X.500 Directory Services [X.501], such as those accessible using the Lightweight Directory Access Protocol (LDAP) RFC4510, an entry is identified by its distinguished name (DN) RFC4512. However, as an entry's DN is not an attribute of the entry, it is not possible to perform attribute value assertions RFC4511 against it.

This document describes the 'entryDN' operational attribute which holds a copy of the entry's distinguished name. This attribute may be used in search filters. For instance, searching the subtree <dc=example,dc=com> with the filter:

  (entryDN:componentFilterMatch:=or:{
      item:{ component "3", rule rdnMatch, value "ou=A" },
      item:{ component "3", rule rdnMatch, value "ou=B" } })

would return entries in the subtree <ou=A,dc=example,dc=com> and entries in subtree <ou=B,dc=example,dc=com>, but would not return any other entries in the subtree <dc=example,dc=com>.

In the above paragraph, DNs are presented using the string representation defined in RFC4514, and the example search filter is presented using the string representation defined in RFC4515 with whitespace (line breaks and indentation) added to improve readability. The 'componentFilterMatch' and 'rdnMatch' rules are specified in RFC3687.

Schema definitions are provided using LDAP description formats RFC4512. Definitions provided here are formatted (line wrapped) for readability.

'entryDN' Operational Attribute

The 'entryDN' operational attribute provides a copy of the entry's current DN.

The following is an LDAP attribute type description suitable for publication in subschema subentries.

  ( 1.3.6.1.1.20 NAME 'entryDN'
      DESC 'DN of the entry'
      EQUALITY distinguishedNameMatch
      SYNTAX 1.3.6.1.4.1.1466.115.121.1.12
      SINGLE-VALUE
      NO-USER-MODIFICATION
      USAGE directoryOperation )

Note that the DN of the entry cannot be modified through this attribute.

Security Considerations

As this attribute only provides an additional mechanism to access an entry's DN, the introduction of this attribute is not believed to introduce new security considerations.

IANA Considerations

Object Identifier Registration

IANA has registered (upon Standards Action) an LDAP Object Identifier RFC4520 for use in this document.

  Subject: Request for LDAP OID Registration
  Person & email address to contact for further information:
      Kurt Zeilenga <[email protected]>
  Specification: RFC 5020
  Author/Change Controller: IESG
  Comments:
      Identifies the 'entryDN' attribute type

'entryDN' Descriptor Registration

IANA has registered (upon Standards Action) the LDAP 'entryDN' descriptor RFC4520.

  Subject: Request for LDAP Descriptor Registration
  Descriptor (short name): entryDN
  Object Identifier: 1.3.6.1.1.20
  Person & email address to contact for further information:
      Kurt Zeilenga <[email protected]>
  Usage: Attribute Type
  Specification: RFC 5020
  Author/Change Controller: IESG

References

Normative References

RFC4510 Zeilenga, K., Ed., "Lightweight Directory Access Protocol

           (LDAP): Technical Specification Road Map", RFC 4510, June
           2006.

RFC4512 Zeilenga, K., Ed., "Lightweight Directory Access Protocol

           (LDAP): Directory Information Models", RFC 4512, June
           2006.

[X.501] International Telecommunication Union - Telecommunication

           Standardization Sector, "The Directory -- Models,"
           X.501(1993) (also ISO/IEC 9594-2:1994).

Informative References

RFC3687 Legg, S., "Lightweight Directory Access Protocol (LDAP)

           and X.500 Component Matching Rules", RFC 3687, February
           2004.

RFC4511 Sermersheim, J., Ed., "Lightweight Directory Access

           Protocol (LDAP): The Protocol", RFC 4511, June 2006.

RFC4514 Zeilenga, K., Ed., "Lightweight Directory Access Protocol

           (LDAP): String Representation of Distinguished Names",
           RFC 4514, June 2006.

RFC4515 Smith, M., Ed., and T. Howes, "Lightweight Directory

           Access Protocol (LDAP): String Representation of Search
           Filters", RFC 4515, June 2006.

RFC4520 Zeilenga, K., "Internet Assigned Numbers Authority (IANA)

           Considerations for the Lightweight Directory Access
           Protocol (LDAP)", BCP 64, RFC 4520, June 2006.

Author's Address

Kurt D. Zeilenga Isode Limited

EMail: [email protected]

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