<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="https://help.joomla.org/proxy/index.php?keyref=Help38:Extensions_Plugin_Manager_Edit#Authentication_-_GMail">Help</a></li></ul><p>Default off:</p><ul><li>Gmail <a href="https://help.joomla.org/proxy/index.php?keyref=Help38:Extensions_Plugin_Manager_Edit#Authentication_-_GMail">Help</a></li><li>LDAP <a href="https://help.joomla.org/proxy/index.php?keyref=Help38:Extensions_Plugin_Manager_Edit#Authentication_-_LDAP">Help</a></li></ul>