查看已开放的端口
firewall-cmd –list-ports
开放端口（开放后需要要重启防火墙才生效）
firewall-cmd –zone=public –add-port=3338/tcp –permanent
关闭端口（关闭后需要要重启防火墙才生效）
firewall-cmd –zone=public –remove-port=3338/tcp –permanent
重启防火墙
firewall-cmd –reload
开机启动防火墙
systemctl enable firewalld
开启防火墙
systemctl start firewalld
禁止防火墙开机启动
systemctl disable firewalld
停止防火墙
systemctl stop firewalld