public function connect($host, $port = null, $timeout = 30, $options = array())
    {
        static $streamok;
        //This is enabled by default since 5.0.0 but some providers disable it
        //Check this once and cache the result
        if (is_null($streamok)) {
            $streamok = function_exists('stream_socket_client');
        }
        // Clear errors to avoid confusion
        $this->setError('');
        // Make sure we are __not__ connected
        if ($this->connected()) {
            // Already connected, generate error
            $this->setError('Already connected to a server');
            return false;
        }
        if (empty($port)) {
            $port = self::DEFAULT_SMTP_PORT;
        }
        // Connect to the SMTP server
        $this->edebug(
            "Connection: opening to $host:$port, timeout=$timeout, options=" .
            var_export($options, true),
            self::DEBUG_CONNECTION
        );
        $errno = 0;
        $errstr = '';
        if ($streamok) {
            $socket_context = stream_context_create($options);
            set_error_handler(array($this, 'errorHandler'));
            $this->smtp_conn = stream_socket_client(
                $host . ":" . $port,
                $errno,
                $errstr,
                $timeout,
                STREAM_CLIENT_CONNECT,
                $socket_context
            );
            restore_error_handler();
        } else {
            //Fall back to fsockopen which should work in more places, but is missing some features
            $this->edebug(
                "Connection: stream_socket_client not available, falling back to fsockopen",
                self::DEBUG_CONNECTION
            );
            set_error_handler(array($this, 'errorHandler'));
            $this->smtp_conn = fsockopen(
                $host,
                $port,
                $errno,
                $errstr,
                $timeout
            );
            restore_error_handler();
        }
        // Verify we connected properly
        if (!is_resource($this->smtp_conn)) {
            $this->setError(
                'Failed to connect to server',
                $errno,
                $errstr
            );
            $this->edebug(
                'SMTP ERROR: ' . $this->error['error']
                . ": $errstr ($errno)",
                self::DEBUG_CLIENT
            );
            return false;
        }
        $this->edebug('Connection: opened', self::DEBUG_CONNECTION);
        // SMTP server can take longer to respond, give longer timeout for first read
        // Windows does not have support for this timeout function
        if (substr(PHP_OS, 0, 3) != 'WIN') {
            $max = ini_get('max_execution_time');
            // Don't bother if unlimited
            if ($max != 0 && $timeout > $max) {
                @set_time_limit($timeout);
            }
            stream_set_timeout($this->smtp_conn, $timeout, 0);
        }
        // Get any announcement
        $announce = $this->get_lines();
        $this->edebug('SERVER -> CLIENT: ' . $announce, self::DEBUG_SERVER);
        return true;
    }