private static boolean isPtp (Configuration config)
    throws IOException
    {
	int	count = config.getNumInterfaces ();

	for (int i = 0; i < count; i++) {
	    Interface	info = config.getInterface (i, 0);
	    if (info.getInterfaceClass () == 6
		    && info.getInterfaceSubClass () == 1
		    && info.getInterfaceProtocol () == 1)
		return true;
	}
	return false;
    }