If you are having issues connecting to your CentOS machine and think that the firewall could be causing the issue then here is how to disable it.
# service iptables save # service iptables stop # chkconfig iptables off
When you've finished your testing you can re-enable the firewall with the following.
# service iptables start # chkconfig iptables on
This helped me a lot when trying to determine whether my machine or router was blocking connection to a certain port.