title: Why is gzip compression not working on IIS 8.5?
body: <p>I am unable to get gzip compression working on IIS 8.5 on a Server 2012 R2 machine.  I have done some research and followed the instructions found in these posts:</p>
  
  <ol>
  <li><a href="https://stackoverflow.com/questions/25580078/how-to-enable-gzip-compression-in-iis-7-5">How to enable GZIP compression in IIS 7.5</a></li>
  <li><a href="https://stackoverflow.com/questions/36727068/compression-in-iis-8-5-not-successful-stating-already-content-encoding">Compression in IIS 8.5 not successful, stating ALREADY_CONTENT_ENCODING</a></li>
  <li><a href="https://stackoverflow.com/questions/6938713/gzip-compression-on-iis-7-5-is-not-working">GZip Compression On IIS 7.5 is not working</a></li>
  <li><a href="https://stackoverflow.com/questions/37945845/gzip-compression-not-working-with-iis-8-5">gzip compression not working with IIS 8.5</a></li>
  </ol>
  
  <p>Here is the relevant section of my config:</p>
  
  <pre><code>&lt;httpCompression directory="%SystemDrive%\inetpub\temp\IIS Temporary Compressed Files" staticCompressionIgnoreHitFrequency="true"&gt;
      &lt;scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" /&gt;
      &lt;!-- I have read that dynamic compression increases server CPU load.
      &lt;dynamicTypes&gt;
          &lt;add mimeType="text/*" enabled="true"/&gt;
          &lt;add mimeType="message/*" enabled="true"/&gt;
          &lt;add mimeType="application/javascript" enabled="true"/&gt;
          &lt;add mimeType="*/*" enabled="false"/&gt;
      &lt;/dynamicTypes&gt;
      --&gt;
      &lt;staticTypes&gt;
          &lt;add mimeType="text/*" enabled="true" /&gt;
          &lt;add mimeType="message/*" enabled="true" /&gt;
          &lt;add mimeType="application/javascript" enabled="true" /&gt;
          &lt;add mimeType="*/*" enabled="false" /&gt;
      &lt;/staticTypes&gt;
  &lt;/httpCompression&gt;
  &lt;urlCompression doStaticCompression="true" doDynamicCompression="true" /&gt;
  </code></pre>
  
  <p>Also, in IIS, I set compression to apply to anything larger than 256 bytes.  And I have performed iisreset.  </p>
  
  <p>Nonetheless, I don't see the compression mentioned in my dev console in Chrome or IE and PageSpeed still tells me to compress stuff.  What simple step have I missed?</p>