iptables on centos 7 how to use code example

Example: centos 7 install iptables

sudo systemctl stop firewalld

sudo systemctl disable firewalld

sudo systemctl mask --now firewalld

sudo yum remove firewalld

sudo yum install iptables-services

sudo systemctl start iptables

sudo systemctl enable iptables

sudo systemctl status iptables

sudo iptables -nvL