centos 7, disable firewalld , add iptables

disable firewalld
> systemctl disable firewalld

install iptables-services , then modify settings
> yum install iptables-services
> vi /etc/sysconfig/iptables

enable iptables to make it autostart, and start iptables rightaway
> systemctl enable iptables
> systemctl start iptables
> iptables -L -n