We have a problem occuring on some of our developer workstations: when visiting a URL without a filename (e.g. http://localhost/), IIS 7 returns a 404 error. Everyone is running Windows 7/IIS 7.5 and ASP.NET 4.0. The application pool is configured to use Classic pipeline mode.
Default documents are enabled, and default.aspx is in the default document list.
I enabled failed request tracing, and see this in the log:
OldHandlerName="", NewHandlerName="ExtensionlessUrl-ISAPI-4.0_64bit",
NewHandlerModules="IsapiModule",
NewHandlerScriptProcessor="C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll", NewHandlerType=""
Later on, I see that this IsapiModule is rejecting the request:
ModuleName="IsapiModule", Notification="EXECUTE_REQUEST_HANDLER", HttpStatus="404",
HttpReason="Not Found", HttpSubStatus="0",
ErrorCode="The operation completed successfully. (0x0)", ConfigExceptionInfo=""
It looks like IIS thinks the ExtensionlessUrl-ISAPI-4.0-64bit should be handling the request. When I look at that module's configuration, it shows that it should be matching path *., so I'm confused why it is matching no path.
A Google search turns up this post on the IIS.net forums from 2005. Unfortunately, no solutions are offered, just an acknowledgement of the problem.
When I update my app pool to use integrated mode, the problem goes away. Unfortunately, it has to run in Classic mode.
What can I do to get IIS to server our default documents again?