How to start / stop / restart / reload iptables on CentOS 7 / RHEL 7

Step 1 : Install iptables-services

yum install iptables-services

Step 2 : Manage iptables with systemctl

Use the below given syntax
systemctl [stop|start|restart|reload] iptables
Example.
To start iptables

systemctl start iptables

To stop iptables

systemctl stop iptables

To restart iptables

systemctl restart iptables

To reload iptables

systemctl reload iptables

Disable starting with OS :

[root@kilo ~]# chkconfig firewalld off
Note: Forwarding request to 'systemctl disable firewalld.service'.
Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@kilo ~]#