public function redirect()
    {
        $url = Common::getRequestVar('url', '', 'string', $_GET);
        if (!UrlHelper::isLookLikeUrl($url)) {
            die('Please check the &url= parameter: it should to be a valid URL');
        }
        // validate referrer
        $referrer = Url::getReferrer();
        if (empty($referrer) || !Url::isLocalUrl($referrer)) {
            die('Invalid Referrer detected - This means that your web browser is not sending the "Referrer URL" which is
				required to proceed with the redirect. Verify your browser settings and add-ons, to check why your browser
				 is not sending this referrer.

				<br/><br/>You can access the page at: ' . $url);
        }

        // mask visits to *.piwik.org
        if (!self::isPiwikUrl($url)) {
            Piwik::checkUserHasSomeViewAccess();
        }
        Common::sendHeader('Content-Type: text/html; charset=utf-8');
        echo '<html><head><meta http-equiv="refresh" content="0;url=' . $url . '" /></head></html>';

        exit;
    }