===Best Practices===

:*When you install Iptables in CentOS it already has some rules predefined.

:*You will always get the default rules if you restart the iptables service.

<ol><li value="4">'''If your command didn't work:'''<ul><li>'''Reload the default rules'''. You can do that by restarting the iptables service (you can also do that at the beginning of your shell script).</li><li>Then '''run your script with all the working iptables commands''' that you already finished.</li><li>'''Return to work on creating the rule that didn't work'''.</li></ul></li></ol>

===Creating Customized Chains===