Install iptables with centos 7

Stop and mask the firewalld service

$ systemctl stop firewalld

$ systemctl mask firewalld

Install and configure iptables

1. $ yum install iptables-services
   

Enable the service to start at boot time by running the following commands:

$ systemctl enable iptables

$ systemctl enable ip6tables

$ systemctl restart iptables
$ systemctl restart ip6tables