public function dnExists($dn)
    {
        if (PEAR::isError($dn)) {
            return $dn;
        }
        if ($dn instanceof Net_LDAP2_Entry) {
             $dn = $dn->dn();
        }
        if (false === is_string($dn)) {
            return PEAR::raiseError('Parameter $dn is not a string nor an entry object!');
        }

        // search LDAP for that DN by performing a baselevel search for any
        // object. We can only find the DN in question this way, or nothing.
        $s_opts = array(
            'scope'      => 'base',
            'sizelimit'  => 1,
            'attributes' => '1.1' // select no attrs
        );
        $search = $this->search($dn, '(objectClass=*)', $s_opts);

        if (self::isError($search)) {
            return $search;
        }

        // retun wehter the DN exists; that is, we found an entry
        return ($search->count() == 0)? false : true;
    }