title: HTTP Cache Control max-age, must-revalidate
body: <p>I have  a couple of queries related to Cache-Control.</p>
  
  <p>If I specify Cache-Control <code>max-age=3600, must-revalidate</code> for a static html/js/images/css file, with Last Modified Header defined in HTTP header:</p>
  
  <ol>
  <li>Does browser/proxy cache(like Squid/Akamai) go all the way to origin server to validate <strong>before max-age expires</strong>? Or will it serve content from cache till max-age expires?</li>
  <li>After max-age expiry (that is expiry from cache), is there a If-Modified-Since check or is content re-downloaded from origin server w/o If-Modified-Since check?</li>
  </ol>