Today in class we were talking about how you needed to save your iptables changes using service iptables save before rebooting at the end of the test, or else you'll fail that section of the test. I brought up the setting IPTABLES_SAVE_ON_STOP to "yes" in /etc/sysconfig/iptables-config, and no one else knew about that file. There's some pretty cool settings in there - read on for details.