the “”App_Offline.htm”” feature in ASP.NET 2.0 provides a super convenient way to bring down an ASP.NET application while you make changes to it (for example: updating a lot of content or making big changes to the site where you want to ensure that no users are accessing the application until all changes are done).
The way app_offline.htm works is that you place this file in the root of the application. When ASP.NET sees it, it will shut-down the app-domain for the application (and not restart it for requests) and instead send back the contents of the app_offline.htm file in response to all new dynamic requests for the application. When you are done updating the site, just delete the file and it will come back online.
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