If a browser sends my server this header
If-Modified-Since: 1230768000 GMT
If the timestamp is less than one year old I want to respond to the browser with a 304 header and NOTHING else.
I know how to do this with PHP:
However I want to do this ONLY with httpd.conf or .htaccess so it applies to ALL images, documents and other files in a directory, not just PHP scripts.