protected function connect()
    {
        $errstr = '';
        $errno  = 0;

        $this->log('creating socket ... ', Net_Notifier_Logger::VERBOSITY_ALL);

        try {
            $this->socket = new Net_Notifier_Socket_Server(
                sprintf(
                    'tcp://0.0.0.0:%s',
                    $this->port
                ),
                null
            );
        } catch (Net_Notifier_Socket_Exception $e) {
            $this->log(
                'failed' . PHP_EOL,
                Net_Notifier_Logger::VERBOSITY_ALL,
                false
            );
            throw $e;
        }

        $this->log('done' . PHP_EOL, Net_Notifier_Logger::VERBOSITY_ALL, false);

        $this->connected = true;
    }