protected function _bindLdapAdminUser()
    {
        $connect = $this->_getLinkId();
        if (!$connect) {
            jLog::log('ldapdao: impossible to connect to ldap', 'auth');
            return false;
        }

        if ($this->_params['adminUserDn'] == '') {
            $bind = ldap_bind($connect);
        } else {
            $bind = ldap_bind($connect, $this->_params['adminUserDn'], $this->_params['adminPassword']);
        }
        if (!$bind) {
            if ($this->_params['adminUserDn'] == '') {
                jLog::log('ldapdao: impossible to authenticate to ldap as anonymous admin user', 'auth');
            } else {
                jLog::log('ldapdao: impossible to authenticate to ldap with admin user '.$this->_params['adminUserDn'], 'auth');
            }
            ldap_close($connect);
            return false;
        }
        return $connect;
    }