title: PHP is_dir() not working for windows network
body: <p>My PHP code looks like this:</p>
  
  <pre><code>$dirpath = "\\\\172.16.111.91\\Data";
  $dircheck = is_dir($dirpath);
  if ($dircheck) {
      echo "Found";
  } else {
      echo "Not Found";
  }
  </code></pre>
  
  <p>If $dirpath is something like "C:/", it works fine, but I've been giving it the UNC path to a remote directory and suddenly it can't find anything.  </p>
  
  <p>I've tried <code>exec("NET USE $dirpath $password /USER:$user");</code> and that doesn't help.</p>
  
  <p>I'm running this on Windows Server 2012 R2, PHP is v5.3, and IIS 8.5.  I think this has something to do with IIS's authentication but for the life of me I just can't figure this one out.</p>