centos7
1.查看firewalld状态:systemctl status firewalld,如果是dead状态,即防火墙未开启。
![](https://img2018.cnblogs.com/blog/701047/201902/701047-20190214022154356-773985323.png)
2.开启防火墙systemctl start firewalld
3.确认firewalld状态:systemctl status firewalld
![](https://img2018.cnblogs.com/blog/701047/201902/701047-20190214022637393-1027024610.png)
4.开放默认端口号 3306,出现success表示成功
firewall-cmd --permanent --zone=public --add-port=3306/tcp
![](https://img2018.cnblogs.com/blog/701047/201902/701047-20190214022844601-1890207444.png)
关闭防火墙:systemctl stop firewalld