说明：  telnet是明文传送口令和数据的，如果你对其默认的设置不满意，有必要对其服务范围进行限制。假设你的主机的ip是210.45.160.17，就可以按如下方式设置了，^_^!
(telnet is plain text passwords and data transfer, if you are not satisfied with its default settings, it is necessary to limit the scope of its services. Assuming your host ip is 210.45.160.17, to be set as follows ,^_^!)