1、测试主机linux主机是否安装该命令工具，出现以下提示说明nc命令未安装
[root@localhost ~]# nc -l 8888
-bash: nc: command not found
2、安装nc命令
root@localhost ~]# yum install -y nc
3、查看当前启动的端口
[root@localhost ~]# netstat -luntp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1355/sshd
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 2416/master
tcp6 0 0 :::22 :::* LISTEN 1355/sshd
tcp6 0 0 ::1:25 :::* LISTEN 2416/master
udp 0 0 0.0.0.0:68 0.0.0.0:* 10838/dhclient
udp 0 0 0.0.0.0:8561 0.0.0.0:* 10838/dhclient
udp6 0 0 :::6388 :::* 10838/dhclient
[root@localhost ~]# nc -l 8888
4、启动测试端口
[root@localhost ~]# nc -l 8888
5、确认端口是否已经有8888的端口
[root@localhost ~]# netstat -luntp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1355/sshd
tcp 0 0 0.0.0.0:8888 0.0.0.0:* LISTEN 20289/nc
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 2416/master
tcp6 0 0 :::22 :::* LISTEN 1355/sshd
tcp6 0 0 :::8888 :::* LISTEN 20289/nc
tcp6 0 0 ::1:25 :::* LISTEN 2416/master
udp 0 0 0.0.0.0:68 0.0.0.0:* 10838/dhclient
udp 0 0 0.0.0.0:8561 0.0.0.0:* 10838/dhclient
udp6 0 0 :::6388 :::* 10838/dhclient
6、好了现在可以进行其他相关测试了