How to open and close the firewall (linux system)?

systemctl start firewalld 启动防火墙

systemctl stop firewalld 关闭防火墙

systemctl status firewalld 查看状态

systemctl disable firewalld 开机禁用

systemctl enable firewalld 开机启用

First check the firewall status

systemctl status firewalld view status

 Then we have to close the firewall ( restart fails ), enter

systemctl stop firewalld

Then we check the status again, which is currently closed.

You can also set

Enable at boot:

systemctl enable firewalld

Boot disabled:

systemctl disable firewalld