Basic use of firewalld
Basic command
Start: systemctl start firewalld
Auto-start at boot: systemctl enable firewalld
停止：systemctl disable firewalld
Disable: systemctl stop firewalld
Add a port that needs to be opened:
firewall-cmd --zone=public --add-port=9333/tcp --permanent (–permanent takes effect permanently, and it becomes invalid after restart without this parameter)
Reload to make the port take effect:
firewall-cmd --reload
Remove port:
firewall-cmd --zone=public --remove-port=9333/tcp --permanent
Check whether firewall is running:
systemctl status firewalld or firewall-cmd --state
Check which ports are opened: the xml file under /usr/lib/firewalld/services
Check which ports are opened command line: firewall-cmd --list-ports