How to enable iptables on CentOS 7 / Fedora 20?

iptables is plain old good. How to enable it after I disable firewalld?

First, install the iptables-services package as root:

#  yum install iptables-services

Then, start iptables service as root:

# touch /etc/sysconfig/iptables
# touch /etc/sysconfig/ip6tables
# systemctl start iptables
# systemctl start ip6tables
# systemctl enable iptables
# systemctl enable ip6tables