An Approach for Using LDAP as a Network Information Service
RFC 2307

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Network Working Group                                          L. Howard
Request for Comments: 2307                        Independent Consultant
Category: Experimental                                        March 1998

      An Approach for Using LDAP as a Network Information Service

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  It does not specify an Internet standard of any kind.
   Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

Abstract

   This document describes an experimental mechanism for mapping
   entities related to TCP/IP and the UNIX system into X.500 [X500]
   entries so that they may be resolved with the Lightweight Directory
   Access Protocol [RFC2251]. A set of attribute types and object
   classes are proposed, along with specific guidelines for interpreting
   them.

   The intention is to assist the deployment of LDAP as an
   organizational nameservice. No proposed solutions are intended as
   standards for the Internet. Rather, it is hoped that a general
   consensus will emerge as to the appropriate solution to such
   problems, leading eventually to the adoption of standards. The
   proposed mechanism has already been implemented with some success.

1. Background and Motivation

   The UNIX (R) operating system, and its derivatives (specifically,
   those which support TCP/IP and conform to the X/Open Single UNIX
   specification [XOPEN]) require a means of looking up entities, by
   matching them against search criteria or by enumeration. (Other
   operating systems that support TCP/IP may provide some means of
   resolving some of these entities. This schema is applicable to those
   environments also.)

   These entities include users, groups, IP services (which map names to
   IP ports and protocols, and vice versa), IP protocols (which map
   names to IP protocol numbers and vice versa), RPCs (which map names
   to ONC Remote Procedure Call [RFC1057] numbers and vice versa), NIS

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RFC 2307      Using LDAP as a Network Information Service     March 1998

   netgroups, booting information (boot parameters and MAC address
   mappings), filesystem mounts, IP hosts and networks, and RFC822 mail
   aliases.

   Resolution requests are made through a set of C functions, provided
   in the UNIX system's C library. For example, the UNIX system utility
   "ls", which enumerates the contents of a filesystem directory, uses
   the C library function getpwuid() in order to map user IDs to login
   names. Once the request is made, it is resolved using a "nameservice"
   which is supported by the client library. The nameservice may be, at
   its simplest, a collection of files in the local filesystem which are
   opened and searched by the C library. Other common nameservices
   include the Network Information Service (NIS) and the Domain Name
   System (DNS). (The latter is typically used for resolving hosts,
   services and networks.) Both these nameservices have the advantage of
   being distributed and thus permitting a common set of entities to be
   shared amongst many clients.

   LDAP is a distributed, hierarchical directory service access protocol
   which is used to access repositories of users and other network-
   related entities. Because LDAP is often not tightly integrated with
   the host operating system, information such as users may need to be
   kept both in LDAP and in an operating system supported nameservice
   such as NIS. By using LDAP as the the primary means of resolving
   these entities, these redundancy issues are minimized and the
   scalability of LDAP can be exploited. (By comparison, NIS services
   based on flat files do not have the scalability or extensibility of
   LDAP or X.500.)

   The object classes and attributes defined below are suitable for
   representing the aforementioned entities in a form compatible with
   LDAP and X.500 directory services.

2. General Issues

2.1. Terminology

   The key words "MUST", "SHOULD", and "MAY" used in this document are
   to be interpreted as described in [RFC2119].

   For the purposes of this document, the term "nameservice" refers to a
   service, such as NIS or flat files, that is used by the operating
   system to resolve entities within a single, local naming context.
   Contrast this with a "directory service" such as LDAP, which supports
   extensible schema and multiple naming contexts.

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RFC 2307      Using LDAP as a Network Information Service     March 1998

   The term "NIS-related entities" broadly refers to entities which are
   typically resolved using the Network Information Service. (NIS was
   previously known as YP.) Deploying LDAP for resolving these entities