Aaron Axelsen

LDAP authentication is configured on a site-wide (as opposed to per-blog) level, so only Network Admin accounts have access to the configuration to LDAP connection information.
Please make sure you have PHP compiled with LDAP support. This will show up as an LDAP section in your phpinfo() if it is correct.
Remember – all the code for the plugin was contributed by volunteers, and you can show your gratitude by giving back to the community!
<h3>How It Works</h3>
When enabled, this plugin can automatically create WordPress user accounts and blogs for LDAP-authenticated users. Assuming user credentials authenticate against the LDAP server, creating local accounts and blogs follows this 
algorithm:
Create a new WPMU User, with LDAP username and a randomly generated password. 
Some user information, such as first and last name, is extracted from the 
 information returned from the LDAP server. 
Actions for user creation and activation are triggered. 
The user’s domain / URL are created depending on plugin configuration (i.e., 
 VHost vs SubDir). 
If the option is set, a blog is created, with path and name based on the LDAP 
 username and the blog is activated with the user being Administrator, and 
 appropriate actions are triggered.
It should be noted that even though a random password is created for a user (for WPMU accounts), it is never displayed to the user. This is intentional so that there is no confusion as to which password should be used; it will always be using LDAP credentials. As a result, though, if ever LDAP is disabled or if the server is unavailable, users created with LDAP authentication will be unable to log in unless their passwords are reset.

WPMU Ldap Authentication

A plugin to override the core WordPress authentication method in order to use a LDAP server for authentication.  Currently only supported on MultiSite …

Curtiss Grymala

This plugin allows WordPress to authenticate, authorize, create and update against an Active Directory domain. This plugin is based heavily on the <a href="https://wordpress.org/extend/plugins/active-directory-integration/" rel="ugc">Active Directory Integration</a> plugin, but has been modified to work with Multi Site and even Multi Network installations of WordPress.
Some of the features included in this plugin are:
<ul>
<li>authenticate against more than one AD Server (for balanced load)</li>
<li>authorize users by Active Directory group memberships</li>
<li>auto create and update users that can authenticate against AD 
mapping of AD groups to WordPress roles</li>
<li>use TLS (or LDAPS) for secure communication to AD Servers (recommended)</li>
<li>use non standard port for communication to AD Servers</li>
<li>protection against brute force attacks</li>
<li>user and/or admin e-mail notification on failed login attempts</li>
<li>determine WP display name from AD attributes (sAMAccountName, displayName, description, SN, CN, givenName or mail)</li>
<li>enable/disable password changes for local (non AD) WP users</li>
<li>WordPress 3.0/3.1 compatibility, including Multi Site and Multi Network</li>
</ul>
This plugin is based on <a href="https://wordpress.org/extend/plugins/active-directory-integration/" rel="ugc">glatze’s Active Directory Integration</a> plugin, which is based upon <a href="https://wordpress.org/extend/plugins/active-directory-authentication/" rel="ugc">Jonathan Marc Bearak’s Active Directory Authentication</a> plugin and <a href="http://adldap.sourceforge.net/" rel="nofollow ugc">Scott Barnett’s adLDAP</a>, a very useful PHP class.
Aside from the changes to make this plugin work more effectively with WordPress Multi Site, this version of the plugin also encrypts the password used to connect to the AD server when it is stored in the database.
This plugin was developed by <a href="https://wordpress.org/extend/plugins/profile/cgrymala" rel="ugc">Curtiss Grymala</a> for the <a href="http://umw.edu/" rel="nofollow ugc">University of Mary Washington</a>. It is licensed under the GPL2, which basically means you can take it, break it and change it any way you want, as long as the original credit and license information remains somewhere in the package.
<h3>Important Notice</h3>
Since I don’t currently have access to multiple AD servers, this plugin has only been tested on a single installation of WordPress with a single AD server. Therefore, it is entirely possible that there are major bugs.
At this time, I am seeking people to test the plugin, so please report any issues you encounter.
<h3>Requirements</h3>
<ul>
<li>
This plugin requires WordPress. It might work with versions older than 3.0, but it has not been tested with those.
</li>
<li>
This plugin also requires PHP5. Some attempt has been made to make it compatible with PHP4, but it has not been tested in that environment.
</li>
<li>
This plugin requires LDAP support to be compiled into PHP. If the <code>ldap_connect()</code> function is not available, this plugin will output an error message and will not do anything.
</li>
</ul>
<h3>To Do</h3>
<ul>
<li>Add ability to validate against multiple AD servers (check one, then the other – rather than just load-balancing as the plugin currently does)</li>
<li>DONE as of 0.4a – Update admin interface to utilize native meta box interface rather than custom layout</li>
<li>DONE as of 0.3a – Separate the profile information from the role equivalent groups in the “auto update user” setting</li>
</ul>

Active Directory Authentication Integration

Allows WordPress to authenticate, authorize, create and update users through Active Directory

WPMU Ldap Authentication vs Active Directory Authentication Integration