IIS6: 404 Error serving content with .com in URL

We ran into an issue today where a customer was having problems serving content from a folder named “example.com”. IIS6 was simply returning a 404 error. I immediately suspected something like URLScan but I eventually found it was due to the execute permissions configured on the parent virtual directory. When the customer configured the virtual directory, they set the execute permissions to “Scripts and executables”. This means that IIS will try to run any cgi compliant executables (.com and .exe files by default) in the virtual directory. In order to run the application, the executable also needs to be authorized in Web Service Extensions.

However, in this case, the URL simply contained “example.com” in the URL: http://server/example.com/images/image1.jpg and we were not trying to run an application. IIS was seeing the “example.com” in the URL and assuming it was a cgi executable and attempting to run the application. However, the file “example.com” did not exist and was therefore returning a 404 error. To correct the issue, we simply set the execute permissions to “None” since the customer was attempting to serve static content, though you can also use “Scripts only”.

The key to this is that there does not need to be a specifc mapping for executables. IIS 6 will attempt to run any executable if the vdir is configured with “Scripts and executables” permissions.