例如我想开放80端口，那么命令就是：

firewall-cmd --zone=public --add-port=80/tcp --permanent

firewall-cmd --reload

centos 关闭防火墙 systemctl stop firewalld.service

查看防火墙状态 firewall-cmd --state

centOS7.4 关闭防火墙 systemctl stop firewalld.service

禁用防火墙 sudo systemctl disable firewalld