<?php
 $adServer = "ldap://WEB-SERVER.domain.com";// set the connection path...
  session_start();// Set if login is required...
    $ldap = ldap_connect($adServer);
    $ldap_id[]    = $ldap;
    $username = 'username';//username for binding...
    $password = 'password';//password for bindind...

    $ldaprdn = 'domain' . "\" . $username;

    ldap_set_option($ldap, LDAP_OPT_PROTOCOL_VERSION, 3);//ldap version...
    ldap_set_option($ldap, LDAP_OPT_REFERRALS, 0);

    $bind = @ldap_bind($ldap, $ldaprdn, $password);//Binding with user...

    if ($bind)
    {
     echo 'connection successful.';
     //Codes tobe executed...
     ldap_unbind($ldap); // Unbind...
    }
    else
    {
      echo 'connection unsuccessful';

?>