<p>The authentication plugins operate when users login to your site or administrator. The Joomla! authentication plugin is in operation by default but you can enable Gmail or LDAP or install a plugin for a different system. An example is included that may be used to create a new authentication plugin.</p>
<p>Default on:</p>
<ul>
<li>Joomla <a href="http://help.joomla.org/proxy/index.php?option=com_help&amp;amp;keyref=Help17:Extensions_Plugin_Manager_Edit#Authentication_-_GMail">Help</a></li>
</ul>
<p>Default off:</p>
<ul>
<li>Gmail <a href="http://help.joomla.org/proxy/index.php?option=com_help&amp;amp;keyref=Help17:Extensions_Plugin_Manager_Edit#Authentication_-_GMail">Help</a></li>
<li>LDAP <a href="http://help.joomla.org/proxy/index.php?option=com_help&amp;amp;keyref=Help17:Extensions_Plugin_Manager_Edit#Authentication_-_LDAP">Help</a></li>
</ul>