Taking Your Site Offline Using an app_offline.htm File

A specific file name recognized by the IIS web server allows you to take your website offline and shut it down. 

Since it's an HTML file, you can add HTML markup to display content. 

The file name is app_offline.htm(l), and it needs to be created using any text editor and then uploaded to the root directory for it to work. 

<!DOCTYPE html>
    <title>Site Under Construction</title>

        <div class="message">
            <p>Sorry, this site is currently under construction.</p>
            <p>We're working hard to bring you something awesome. Check back soon!</p>


Once uploaded, it will take your site offline and intercept all new web requests so that only its content will be displayed. 

It's a valuable tool when updating your website because you can create a "Site Temporarily Unavailable," "Under Maintenance," or any other page you want to display. At the same time, you silently make updates to other parts of your site. Once the updates are done, rename or delete the file to resume normal site operations.