title: AUTH_USER vs LOGON_USER vs REMOTE_USER
body: <p>I'm wanting to be able to get the information of the logged in user when they come on to our site so they don't need to log in. 
  I've been told that it's only possible in I.E when your on windows IE. once they have signed in with their windows credentials.</p>
  
  <p>I've searched the net and all three of these (<code>$_SERVER['AUTH_USER']</code>, <code>$_SERVER['LOGON_USER']</code>, <code>$_SERVER['REMOTE_USER']</code>) had been recommended so I'm not sure which one to check. </p>
  
  <p>Second of all, I'm using windows server with IIS and no matter what I've tried and searched for on the net but nothing works. 
  I can see the variables in the <code>$_SERVER</code> but all the above are empty strings.</p>
  
  <p>How do I fix this problem?</p>
  
  <p>For reference I'm using windows server 2012 with php v7.1</p>
  
  <p>Also in my php.ini file I see that all of them have the following values.   </p>
  
  <p><code>$_SERVER['LOGON_USER']: no value</code>  (like so)</p>
  
  <p>but I've also searched on how to set these in the .ini file without much luck.</p>
  
  <pre><code>header('WWW-Authenticate: NTLM', true);
  
  
  // with this die there is a user and password prompt 
  // if i click cancel then it sends the information through to the 
  // server vars as expected.     
  // when we cancel here it registers as two requests as my logs in the 
  // log shows up two times.
  
  // without it the login page loads with symfony but no values ever
  // come through and i cant log in the user. 
  die();
  </code></pre>