1.只能测试tcp端口

telnet IPADDR PORT

2.可以测试tcp及udp端口

安装nc

nc -uvz 172.19.17.141 80-8080

注（man说明）：

-u      Use UDP instead of the default option of TCP.

-v      Have nc give more verbose output.

-z      Specifies that nc should just scan for listening daemons, without

             sending any data to them.  It is an error to use this option in

             conjunction with the -l option.

简单起见，可以直接用：

nc -z 172.19.17.141 80-8080