How To: Disable Firewall on RHEL / CentOS / RedHat Linux

http://www.cyberciti.biz/faq/disable-linux-firewall-under-centos-rhel-fedora/

Next enter the following three commands to disable firewall.
# service iptables save
# service iptables stop
# chkconfig iptables off

If you are using IPv6 firewall, enter:
# service ip6tables save
# service ip6tables stop
# chkconfig ip6tables off