centos7中设置防火墙

开启firewall：systemctl start firewalld.service
停止firewall：systemctl stop firewalld.service
禁止firewall开机启动：systemctl disable firewalld.service
开放端口：
firewall-cmd --zone=public --add-port=22/tcp --permanent
原文：https://blog.youkuaiyun.com/hiqingtian/article/details/79027104