Lightweight Directory Access Protocol (LDAP): Uniform Resource Locator
RFC 4516

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Network Working Group                                      M. Smith, Ed.
Request for Comments: 4516                           Pearl Crescent, LLC
Obsoletes: 2255                                                 T. Howes
Category: Standards Track                                  Opsware, Inc.
                                                               June 2006

             Lightweight Directory Access Protocol (LDAP):
                        Uniform Resource Locator

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

   This document describes a format for a Lightweight Directory Access
   Protocol (LDAP) Uniform Resource Locator (URL).  An LDAP URL
   describes an LDAP search operation that is used to retrieve
   information from an LDAP directory, or, in the context of an LDAP
   referral or reference, an LDAP URL describes a service where an LDAP
   operation may be progressed.

Table of Contents

   1. Introduction ....................................................2
   2. URL Definition ..................................................2
      2.1. Percent-Encoding ...........................................4
   3. Defaults for Fields of the LDAP URL .............................5
   4. Examples ........................................................6
   5. Security Considerations .........................................8
   6. Normative References ............................................9
   7. Informative References .........................................10
   8. Acknowledgements ...............................................10
   Appendix A: Changes Since RFC 2255 ................................11
      A.1. Technical Changes .........................................11
      A.2. Editorial Changes .........................................11

Smith & Howes               Standards Track                     [Page 1]
RFC 4516             LDAP: Uniform Resource Locator            June 2006

1.  Introduction

   LDAP is the Lightweight Directory Access Protocol [RFC4510].  This
   document specifies the LDAP URL format for version 3 of LDAP and
   clarifies how LDAP URLs are resolved.  This document also defines an
   extension mechanism for LDAP URLs.  This mechanism may be used to
   provide access to new LDAP extensions.

   Note that not all the parameters of the LDAP search operation
   described in [RFC4511] can be expressed using the format defined in
   this document.  Note also that URLs may be used to represent
   reference knowledge, including that for non-search operations.

   This document is an integral part of the LDAP technical specification
   [RFC4510], which obsoletes the previously defined LDAP technical
   specification, RFC 3377, in its entirety.

   This document replaces RFC 2255.  See Appendix A for a list of
   changes relative to RFC 2255.

   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.  URL Definition

   An LDAP URL begins with the protocol prefix "ldap" and is defined by
   the following grammar, following the ABNF notation defined in
   [RFC4234].

      ldapurl     = scheme COLON SLASH SLASH [host [COLON port]]
                       [SLASH dn [QUESTION [attributes]
                       [QUESTION [scope] [QUESTION [filter]
                       [QUESTION extensions]]]]]
                                      ; <host> and <port> are defined
                                      ;   in Sections 3.2.2 and 3.2.3
                                      ;   of [RFC3986].
                                      ; <filter> is from Section 3 of
                                      ;   [RFC4515], subject to the
                                      ;   provisions of the
                                      ;   "Percent-Encoding" section
                                      ;   below.

      scheme      = "ldap"

Smith & Howes               Standards Track                     [Page 2]
RFC 4516             LDAP: Uniform Resource Locator            June 2006

      dn          = distinguishedName ; From Section 3 of [RFC4514],
                                      ; subject to the provisions of
                                      ; the "Percent-Encoding"
                                      ; section below.

      attributes  = attrdesc *(COMMA attrdesc)
      attrdesc    = selector *(COMMA selector)
      selector    = attributeSelector ; From Section 4.5.1 of
                                      ; [RFC4511], subject to the