1.查看防火墙状态
systemctl status firewalld.service // 查看
systemctl start firewalld // 开启
systemctl stop firewalld // 关闭
2.查看端口情况
firewall-cmd --list-all
3.打开端口
firewall-cmd --add-port=80/tcp --permanent
4.重启防火墙
sudo firewall-cmd --reload