To add an unknown extension in IIS

To add an unknown extension in IIS for your IIS to detect that extension perform the following steps.

To define a MIME type for a specific extension, follow these steps:

1. Open the IIS Microsoft Management Console (MMC), right-click the local computer name, and then click Properties.
2. Click MIME Types.
3. Click New.
4. In the Extension box, type the file name extension that you want (for example, .pdb).
5. In the MIME Type box, type application/octet-stream.
6. Apply the new settings. Note that you must restart the World Wide Web Publishing Service or wait for the worker process to recycle for the changes to take effect. In this example, IIS now serves files with the .pdb extension.