Zend Framework 1.9.9 Manual

$options = array(/* ... */);
$ldap = new Zend_Ldap($options);
$ldap->bind();
$ri = new RecursiveIteratorIterator($ldap->getBaseNode(),
                                    RecursiveIteratorIterator::SELF_FIRST);
foreach ($ri as $rdn => $n) {
    var_dump($n);
}