How to permanently disable firewall in Red Hat Linux

I have followed the below steps to disable the firewall in Linux. After reboot, again firewall is enabled. How to disable firewall permanently?

1. Login as the root user.

2. Next enter the following three commands to disable firewall.

   service iptables save  
   service iptables stop  
   chkconfig iptables off  
   

3. Disable IPv6 firewall.

   service ip6tables save  
   service ip6tables stop  
   chkconfig ip6tables off  
   

For version 7 of CentOS or RedHat Enterprise you must use the command systemctl.

For example:

#Check status:

systemctl status firewalld

#Stop firewall:

systemctl stop firewalld

#Disable firewall:

systemctl disable firewalld

Extracted from: http://www.sysadmit.com/2016/12/linux-deshabilitar-firewall-redhat-centos.html

FYI: This no longer works in RHEL7, and the handy init.d script has been removed.

The following worked for me.

systemctl stop firewalld
systemctl disable firewalld
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT