http://stackoverflow.com/questions/24756240/how-can-i-use-iptables-on-centos-7

# sudo service iptables startRedirecting to /bin/systemctl start  iptables.serviceFailed to issue method call: Unit iptables.service failed to load: No such file or directory.

With RHEL 7 / CentOS 7, firewalld was introduced to manage iptables. IMHO, firewalld is more suited for workstations than for server environments.

It is possible to go back to a more classic iptables setup. First, stop and mask the firewalld service:

systemctl stop firewalldsystemctl mask firewalld

Then, install the iptables-services package:

yum install iptables-services

Enable the service at boot-time:

systemctl enable iptables

Managing the service

systemctl [stop|start|restart] iptables

Saving your firewall rules can be done as follows:

service iptables save

or

/usr/libexec/iptables/iptables.init save

How can i use iptables on centos 7 or fedora?