Website: How to take a Web application offline

To take a Web application offline before deployment

1. Create a file called App_offline.htm and include a message in the file that lets users know that the site is unavailable because you are updating the site.
2. Place the App_offline.htm file in the root folder of the target Web site.
   While the App_offline.htm file exists in the root of your Web site, any request to the Web site will redirect to that file.
   When you have finished deploying the site, remove the App_offline.htm file.