how to start iptables when system upping?

[linux_netfilter]

Hi,all:
   What I want to do is starting iptables and applying my
own ruleset.How to do?I am not familiar with linux.Does
linux run every shell script under /etc/rc.d/init.d?
   There are both iptables and ipchains under /etc/rc.d/init.d.
And ipchains and firewall but no iptables are under /etc/sysconfig.


BTW:I have recompiled the kernel and removed ipchains modules
and add iptables(and related) modules.Now I can run iptables with
my own filter rules after system up.But how to do then iptables can
run with my rules when system upping?


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