The Web Server (IIS) provides web/Windows App clients access to files in the project directory. Since file transfer is a potential security risk, file transfer via IIS is restricted to specific file types. The restriction is set only on those virtual directories in IIS that provide write access to clients. IIS responds with an HTTP 404 error, if a client attempts to access or to upload a file of a different type. Depending on the workflow this error gets reported to the operator at the client, or gets added to the log file on the server.

A list of such allowed file types is maintained in a web.config file of a virtual directory at the following path
[Installation drive:]\[Installation folder]\[Project folder]\[VirtualDirectoryFolder]
where Virtual Directory Folder can be devices, graphics, libraries and profiles.

The allowed file types for each virtual directory mentioned in the web.config file are also configured in IIS using the Request Filtering feature, thus ensuring file transfer only for the specified file types. Note that no request filtering is configured for the shared and documents virtual directories as these are read-only directories. To view the allowed file types for a virtual directory in IIS, do the following: