title: Facebook iFrame application -- IE7 not allowing cookies
body: <p>I know this topic has been covered extensively, but I am totally stuck and in need of some direction and new opinions.  I have a Facebook iFrame application that works perfectly in IE6,8, Safari, Chrome, FF, etc.  Only IE7 gives me grief.</p>
  
  <p>I have created a P3P policy file, and its associated XML file.  The policy fully validates with the P3P policy validator.</p>
  
  <p>As soon as the iFrame loads from within Facebook, the red eye icon appears and when I click it, it reports that cookies from the iFrame's domain are blocked.  I have confirmed that the default 'medium' privacy setting is set on IE7.  Interestingly I've found that by removing Google Analytics, the page will load initially without blocking the cookies, but as soon as the page reloads, or the user logs in, cookies are then blocked again even though the P3P header is sent immediately from every page.  All assets are sent via S3, so there shouldn't be any issues there.</p>
  
  <p>FYI, here's my P3P file; I've tried absolute paths, relative paths, switching order of CP and policyref, and separated the two into separate header calls with no luck.</p>
  
  <pre><code>header('P3P: CP="NON DSP TAIa PSAa PSDa OUR IND UNI", policyref="/w3c/p3p.xml"');
  </code></pre>
  
  <p>I have confirmed that the P3P Header is being sent and received by the browser.  I have added a META p3p tag to the HTML page.  I have removed all redirects.  Still the issue persists.  I've spent so much time looking into this, and I am now out of ideas.  Any thoughts or ideas about how to approach this from a fresh perspective would be greatly appreciated.  I'm using PHP 5.3.5 over NGINX.  No framework being used...</p>