Lightweight Directory Access Protocol

These pages are provided for historical reference only. The LDAP software contained herein is out of date. We suggest parties seeking open source, production quality LDAP software explore OpenLDAP.


The Lightweight Directory Access Protocol (LDAP) is a protocol for accessing online directory services. It runs directly over TCP, and can be used to access a standalone LDAP directory service or to access a directory service that is back-ended by X.500.

A widely used implementation of LDAP was written at the University of Michigan, where development was being supported by the National Science Foundation under Grant No. NCR-9416667. The final release of the U-M LDAP package is available as a compressed Unix tar file:

This software, and its documentation which describes how to use the UM implementation to set up a directory service and also inlcudes an overview of LDAP-based directory service, is provided merely for historical reference. Current software is available from OpenLDAP.

Some other related resources (not at UofM) include:

Resources for Developers

The University of Michigan LDAP implementation includes libraries for writing LDAP clients, and it has been ported to many flavors of Unix as well as to the Macintosh, MS-DOS, Microsoft Windows, and VMS. These libraries are included with the UM LDAP implementation mentioned above:

Mailing Lists

There are several LDAP-related mailing lists that may be of interest:
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