This plugin adds an additional authentication layer to your WordPress installation to put the site into a demo- or maintainance-mode.
When we are working on a new page for a customer, we almost always need to do an online presentation. With this plugin activated, we do not need to expose anything to the rest of the web at that point. Not even that we use WordPress as the CMS.
The authentication form of the plugin accepts login of all your WordPress users. Logged in, these can now see the page just as future visitors will, and as well log in through the WordPress login screen (wp-login.php) to enter the administration backend.