title: IIS website is sending multiple content-type headers for zip files
body: <p>We have a problem with an IIS5 server.</p>
  
  <p>When <em>certain</em> users/browsers click to download .zip files, binary gibberish text sometimes renders in the browser window. The desired behavior is for the file to either download or open with the associated zip application.</p>
  
  <p>Initially, we suspected that the wrong content-type header was set on the file. The IIS tech confirmed that .zip files were being served by IIS with the mime-type "application/x-zip-compressed".</p>
  
  <p>However, an inspection of the HTTP packets using Wireshark reveals that requests for zip files return <strong>two</strong> Content-Type headers.</p>
  
  <ul>
  <li>Content-Type: text/html;
  charset=UTF-8</li>
  <li>Content-Type:
  application/x-zip-compressed</li>
  </ul>
  
  <p>Any idea why IIS is sending <strong>two</strong> content-type headers? This doesn't happen for regular HTML or images files. It does happen with ZIP and PDF.</p>
  
  <p>Is there a particular place we can ask the IIS tech to look? Or is there a configuration file we can examine?</p>