public function extractDomain($sHost)
    {
        $oStr = getStr();
        if (!$oStr->preg_match('/[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}/', $sHost) &&
            ($iLastDot = strrpos($sHost, '.')) !== false
        ) {
            $iLen = $oStr->strlen($sHost);
            if (($iNextDot = strrpos($sHost, '.', ($iLen - $iLastDot + 1) * -1)) !== false) {
                $sHost = trim($oStr->substr($sHost, $iNextDot), '.');
            }
        }

        return $sHost;
    }