CentOS 7.0默认使用的是firewall作为防火墙
1、查看防火墙状态
firewall-cmd --state / sudo systemctl status firewalld
2、停止firewall
systemctl stop firewalld.service / sudo systemctl stop firewalld
3、禁止firewall开机启动
systemctl disable firewalld.service / sudo systemctl disable firewalld