Offline Page
There is a possibility to disable access to the front of your site.
How to enable the offline page? Step 1: Go to "System -> Global Configuration -> Site".Step 2: Click on "Yes" for "Site Offline" option. Step 3: Fill in a text for "Offline Message" to give your visitors some explanation about why your website is unavailable. Step 4: Click on "Save" to save your settings.
How to customize the offline page? You need to edit the following file: /templates/jm-template-name/offline.php