Q. I’d like to start my Iptables based firewall when my computer comes online so that it get protected from the Internet? I’m using CentOS Linux Server version 4.x.

A. CentOS / RHEL / Fedora Linux has service located at /etc/init.d/iptables to start firewall on boot. All you have to do is type the following command to turn on firewall on boot:
# chkconfig iptables on

Your firewall rules are saved at /etc/sysconfig/iptables files.