yum install firewalld
启动： systemctl start firewalld
查看状态： systemctl status firewalld
停止： systemctl disable firewalld
禁用： systemctl stop firewalld
systemctl start firewalld.service //开启防火墙
systemctl stop firewalld.service //关闭防火墙
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
firewall-cmd --reload //在不改变状态的条件下重新加载防火墙
如果启动显示这行代码的话，原因firewalld服务被锁定
[root@localhost ruizukai]# systemctl start firewalld.service
Failed to start firewalld.service: Unit is masked.
解决办法：
[root@localhost ruizukai]# systemctl unmask firewalld
Removed symlink /etc/systemd/system/firewalld.service.
[root@localhost ruizukai]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon 启动成功
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
Active: active (running) since 四 2020-07-02 15:20:12 CST; 8s ago
Docs: man:firewalld(1)
Main PID: 8448 (firewalld)
Tasks: 2
CGroup: /system.slice/firewalld.service
└─8448 /usr/bin/python2 -Es /usr/sbin/firewalld --nofork --nopid
7月 02 15:20:11 localhost.localdomain systemd[1]: Starting firewalld - dynamic firewall daemon...
7月 02 15:20:12 localhost.localdomain systemd[1]: Started firewalld - dynamic firewall daemon.
7月 02 15:20:12 localhost.localdomain firewalld[8448]: WARNING: AllowZoneDrifting is enabled. This is conside...now.
Hint: Some lines were ellipsized, use -l to show in full.
