I have an ASP.NET website, but I would like to display the “under maintenance” page when my customers try to visit the website. Does anyone know how to do this?
If you run the application in the .NET 4.0 application pool (IIS 7.0 or IIS 7.5), or your website is configured as an ASP.NET 4.0 website (IIS 6.0) and would like to show your customers “under maintenance” for a limited time , the easiest way is to put a file called app_offline.htm in the root folder of your website. Then your application will be disconnected, and clients will be served using the app_offline.htm page, regardless of what they want.When you are done with the maintenance, simply delete or rename the file and everything will return to normal.
If you run the application in the .NET 4.0 application pool (IIS 7.0 or IIS 7.5), or your website is configured as an ASP.NET 4.0 website (IIS 6.0) and would like to show your customers “under maintenance” for a limited time , the easiest way is to put a file called app_offline.htm in the root folder of your website. Then your application will be disconnected, and clients will be served using the app_offline.htm page, regardless of what they want.
When you are done with the maintenance, simply delete or rename the file and everything will return to normal.
Source: The easiest way to disable your website (IIS 6.0 or IIS 7.5 with .NET 4.0)