CentOS7下把iptables改成传统方式来使用的办法！
systemctl stop firewalld
systemctl mask firewalld
安装iptables-services：
yum install iptables–services
设置开机启动：
systemctl enable iptables
systemctl [stop|start|restart] iptables
#or
service iptables [stop|start|restart]
service iptables save
#or
/usr/libexec/iptables/iptables.init save