First, need to disable and remove firewalld firewall. Type Following commands:
Optional
#sudo systemctl stop firewalld.service
#sudo systemctl disable firewalld.service
#yum remove firewalld -y
Install iptables firewall on CentOS 7
To install Iptables package type following command:#yum install iptables-services -y
After install iptables firewall, set the iptables service to start automatically with system booting up:
#systemctl enable iptables
if you want to use command “/etc/init.d/iptables save” to save the
firewall policy , you need to update the iptables init script. issue the following command:
cp /usr/libexec/iptables/iptables.init /etc/init.d/iptables
now you can use “/etc/init.d/iptables save ” command.
then you need to allow or deny in iptables file:
#vim /etc/sysconfig/iptables
after Edit we need to restart and then save
#/etc/init.d/iptables restart
#/etc/init.d/iptables save
That’s been all!=================================================
http://lintut.com/install-and-enable-iptables-firewall-on-centos-7-linux/
https://www.digitalocean.com/community/tutorials/how-to-migrate-from-firewalld-to-iptables-on-centos-7
http://sharadchhetri.com/2014/07/26/how-to-start-stop-restart-reload-iptables-on-centos-7-rhel-7/
http://www.cyberciti.biz/faq/rhel-fedorta-linux-iptables-firewall-configuration-tutorial/