I have an issue where I am reverse proxying from an IIS 6.0 server to an apache server which is serving PNG files with no extension. Strangly it serves files with a "." but nothing else, for example:
I tried adding the MIME type "." and even ".*" to the IIS virtual directory and the server (via IIS MMC snap-in) but this hasn't seemed to solve the issue. Adding the mime type worked when testing other obscure extensions e.g. image.x, image.] etc, but if you have the filename and the "." and nothing else after it, it seems to fail with 404.