PHP - LDAP Connection test

<?php
/**
 * PHP-LDAP CONNECTION TEST
 * This is test script to check if LDAP authentication connection is up.
 * The algio here just to show how-to, in production these best in the class setup.
 *
 * Minimum:
 * - PHP 5.5
 * - PHP LDAP Lib
 *
 * Author: junior@coderlogy.com
 *
 * Futher Readings;
 * - [LDAP Port|https://technet.microsoft.com/en-us/library/dd772723(v=ws.10).aspx]
 */

// show all error
error_reporting(E_ALL);

// just a method to print status & terminate this script
function logHere($type, $msg = FALSE) {
  $fatal = FALSE;

  if ($fatal = ($msg === FALSE)) {
    $msg  = $type;
    $type = 'FATAL';
  }

  echo "{$type}:{$msg}" . PHP_EOL;

  if ($fatal) {
    exit;
  }
}

/**
 * CHECK PHP
 * - Do these once only; to check if enviroment have those lib.
 */
if (
  (!extension_loaded('ldap')) ||
  (!function_exists('ldap_connect')) ||
  (!function_exists('ldap_set_option')) ||
  (!function_exists('ldap_search')) ||
  (!function_exists('ldap_get_entries')) ||
  (!defined('LDAP_OPT_PROTOCOL_VERSION')) ||
  (!defined('LDAP_OPT_REFERRALS')) ||
  (!defined('LDAP_OPT_NETWORK_TIMEOUT'))
) {
  // logHere & exit
  logHere('ldap.php-failed-ldap');
}

/**
 * CHECK HOST LOCATION
 * - Do this once only; to check if IP & port welcome Authentication API.
 */
$host = 'xxx.xxx.xxx.xxx'; // <-- CONFIG HERE
// port - these are basic selections suggested by Microsoft TechNet - dd772723.
//      - however each organization might have different setup for security reason.
// $port = 389; // normal - 3268 GC
// $port = 636; // secure - 3269 GC
$port = 88; // Kerberos - User / Comp Autehntication
// $port = 53; // DNS - User / Comp Autehntication
$wait = 5;
$eCode = $eStr = '';
if (!($fp = @fsockopen($host, $port, $eCode, $eStr, $wait))) {
  // logHere & exit
  logHere('error', 'ldap.error-code:' . $eCode);
  logHere('error', 'ldap.error-msg:' . $eStr);
  logHere('ldap.hello-failed');
}
fclose($fp);
logHere('info', 'ldap-fsockopen-success');

/**
 * CHECK LDAP CONNECTION
 * - Check if Host can be connected with PHP Driver.
 */
$con = ldap_connect($host);
if (empty($con)) {
  // logHere & exit
  logHere('ldap.connection-failed');
}
logHere('info', 'ldap-connection-ok');

/**
 * SETUP LDAP CONTROLS
 * - Basic PHP-LDAP options; as needed.
 */
ldap_set_option($con, LDAP_OPT_PROTOCOL_VERSION, 3);
ldap_set_option($con, LDAP_OPT_REFERRALS, 0);
ldap_set_option($con, LDAP_OPT_NETWORK_TIMEOUT, 10);

/**
 * BINDING USER
 * - Authenticate User / Computer via LDAP
 */
$domain   = 'XXXX';         // <-- CONFIG HERE
$username = 'XXX.XXX.XXX';  // <-- CONFIG HERE
$password = 'xXxXxXxXxX';   // <-- CONFIG HERE

$ldaprdn  = "{$domain}\\{$username}";
$bind     = @ldap_bind($con, $ldaprdn, $password);
if (empty($bind)) {
  // get more error details
  $extended_error = ': Unknown issue.';
  $diagMsg = 0x0032; // LDAP_OPT_ERROR_STRING - if version issue (octal)
  ldap_get_option($con, $diagMsg, $extended_error);
  // logHere & exit
  logHere('error', $extended_error);
  logHere('ldap.binding-failed');
}
logHere('info', 'ldap-binding-ok');
logHere('info', 'ldap-authentication-ok');

// all ok