title: Getting blank value for $_SERVER['AUTH_USER']
body: <p>I have a PHP app running on Windows 2008 server R2, which authenticates users against Active Directory using PHP's LDAP library.</p>
  
  <p>As per <a href="https://stackoverflow.com/questions/168610/can-you-get-a-windows-ad-username-in-php">this answer</a>, I'm looking to use <code>$_SERVER['AUTH_USER']</code>, but I'm getting a blank value for it. Same for <code>AUTH_TYPE</code> and <code>AUTH_PASSWORD</code>. The variables are declared, but none of them have any value assigned to them.</p>
  
  <p>I've enabled both the Basic Authentication and Windows Authentication roles (through Server Manager), but neither has solved the issue.</p>
  
  <p>I'm using PHP 5.3.14, Zend Server CE and IIS 7.5. </p>
  
  <p>I need to apply a single sign on solution, but without being able to fetch the currently logged in user's credentials, I'm at a loss.</p>
  
  <p>Any help would be greatly appreciated.</p>