启动：systemctl start firewalld
禁用：systemctl stop firewalld
重新载入规则：firewall-cmd --reload
查看所有打开的端口：firewall-cmd --zone=public --list-ports
临时开放端口：firewall-cmd --zone=public --add-port=3306/tcp
永久开放端口：firewall-cmd --zone=public --add-port=3306/tcp --permanent
移除端口：firewall-cmd --zone=public --remove-port=3306/tcp --permanent
