title: IE on Windows XP not using GeoTrust SSL Certificate (2048bit RSA) but falling back to Self-Signed 1024bit RSA cert
body: <p>This has been driving me crazy, though I suspect the answer may be simple!</p>
  
  <p>One of our clients has a GeoTrust SSL certificate for their domain (more details below), the problem is users on Windows XP aren't getting that certificate in IE  (we had to deploy an intermediary certificate for Firefox, so that may be why that works). Tried in IE 7 &amp; 8 and both are instead sent a self-signed certificate, leading to a browsing error.</p>
  
  <p>IE8 &amp; 9 on Win 7 are fine, they get sent the correct certificate and can view the site without any warnings. It's based on this that I'm surmising it's probably related to XP rather than the browser, though happy to be corrected.</p>
  
  <p>Anyone got any idea why this might be happening (I'd assumed XP couldn't handle the 2048bit root cert, but Google suggests otherwise)? I've installed the latest updates onto my test machine and it still seems to be receiving the wrong key.</p>
  
  <p>Given the nature of the site, installing a CA on user's machines isn't an option, and the client won't be too happy if the answer is "They'll have to ignore it" though obviously if that's what it comes down to...</p>
  
  <p><strong>Certificate details</strong></p>
  
  <ul>
  <li>Issued By GeoTrust DV SSL CA </li>
  <li>Valid: 10/6/2012 - 13/6/2012    </li>
  <li>Cert signature algorithm: PKCS #1 SHA-1 with RSA    </li>
  <li>Pub Key algorithm: PKCS#1 RSA    </li>
  <li>Pub Key length: 2048 bits</li>
  </ul>
  
  <p><strong>Self Signed</strong> </p>
  
  <ul>
  <li>Issued by: localhost.localdomain</li>
  <li>Algorithm: sha1RSA</li>
  <li>Pub Key length: 1024 bits</li>
  </ul>
  
  <p>UPDATE: The client has just reported that they get the error in IE9 on Windows 7 too. Works fine from my testbed, so got some more digging to do I think!</p>