systemctl stop firewalld 关闭防火墙
systemctl status firewalld 查看状态
systemctl disable firewalld 不启动
systemctl enable firewalld 启动
如果使用 service iptables stop 会抛出以下异常
Failed to stop iptables.service: Unit iptables.service not loaded.
原文：https://www.cnblogs.com/liguangming/p/12683758.html