When setting up a system that has never been setup at the previous, I usually turn off the firewall to see if the setup without a firewall is running properly. If it goes well, then the firewall will be enabled. It is often I do to find out wheter there are problems associated with a firewall setup or not.
The firewall serves as a blockade of access from unwanted connections. This facility is an important and commonly used in server environments to restrict any ports that might be accessed, both internally and externally. To disable the firewall on Red Hat Linux system and its derivatives like Fedora, CentOS, or others derivatives, here are two magic commands:
service iptables save
service iptables stop
If you want the firewall does not automatically run at boot time, give the following command:
chkconfig iptables off
If the Linux system is used as server and accessible from the public IP addresses, the firewall should be activated again after the testing process is completed, by providing an exception or allow the service / port which related