title: PHP ldap - Strong(er) authentication required
body: <p>I have a PHP script which does a LDAP connect, bind and search. It is working very well with most of the Active Directory servers, however one of our clients has a problem. The script returns</p>
  
  <pre><code>Strong(er) authentication required.
  </code></pre>
  
  <p>error when trying ldap_bind.</p>
  
  <p>All the searches I made directed me to two possible problems:</p>
  
  <ol>
  <li>I have to set <code>LDAP_OPT_PROTOCOL_VERSION</code> to <code>3</code> - which I do and did before, so this can not be my problem.</li>
  <li>The AD server is configured to use SSL authentication - but our client insists that it is a default Windows 2008 R2 server installation, and that does not default to SSL for sure.</li>
  </ol>
  
  <p>What other causes could be for this error to happen?</p>
  
  <h1>UPDATE</h1>
  
  <p>It was SSL required on Active Directory server ... </p>