LDAP-Login an AD vom Internet aus mittels PHP-Script

<?php
  function ldap_login($server){
      if((isset($_COOKIE["cookie_username"]) AND ($_COOKIE["cookie_password"]))){  
        $username = $_COOKIE["cookie_username"] ;  
        $password = $_COOKIE["cookie_password"] ;  

        $check_positive = 1 ;
      }
      else{
       if((isset($_POST["username"]) OR ($_POST["password"]))){  
         if(empty($_POST["username"]) OR empty($_POST["password"])){  
           $array["login_complete"] = "Bitte füllen Sie alle Felder aus !" ;  
         }
         else{
           if((isset($_POST["username"]) AND ($_POST["password"]))){  
             $username = $_POST["username"] ;  
             $password = $_POST["password"] ;  

             $check_positive = 1 ;
          }
        }
      }
      else{
        $array["login_complete"] = "Sie sind nicht eingeloggt !" ;  
      }
    }

    if($check_positive == 1){
      if(!($connection = ldap_connect($server))){
        $array["login_complete"] = "Verbindung zum Server konnte nicht hergestellt werden !" ;  
      }

      ldap_set_option($connection, LDAP_OPT_PROTOCOL_VERSION, 3) ;
      ldap_set_option($connection, LDAP_OPT_REFERRALS, 0) ;

      if(!($bind = ldap_bind($connection, $username, $password))){
        $array["login_complete"] = "Login fehlgeschlagen !" ;  
      }
      else{
        setcookie("cookie_username", $username, time()+(60*60)) ;  
        setcookie("cookie_password", $password, time()+(60*60)) ;  

        $array["login_check"] = true ;  
      }
    }

    $array["username"] = $username ;  
    $array["password"] = $password ;  
    $array["connection"] = $connection ;  

    return $array ;
  }
?>