Failed to start firewalld.service: Unit firewalld.service is masked

卸载Firewall并安装iptables后重新安装回Firewall。安装Firewall启动时，提示Failed to start firewalld.service: Unit firewalld.service is masked.

搜索尝试了大神们的解决方法，输入指令

systemctl unmask firewalld.service

启动 firewalld.service

systemctl start firewalld.service

把 80 端口添加到防火墙开放端口中

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

重启一遍 firewalld 服务使其生效

systemctl restart firewalld.service

检查更改是否生效

firewall-cmd --zone=public --query-port=80/tcp

systemctl enable firewalld.service  //设置开机自动启动
systemctl disable firewalld.service   //设置关闭开机制动启动