Setting up iptables on Knoppix HD install

Yes, I know I could always apt-get GuardDog or something, but I'm looking to learn about how to set up iptables here, so hear me out.

What I have done is stuck a symbolic link in the /etc/rcS.d directory "S09iptables" and linked it to /etc/init.d/iptables

iptables doesn't work (there are no rules), and I'm not sure where iptables expects a file to be for it, or what it is looking for exactly.

Can anyone help me out here?
And can someone stick a firewall in Knoppix by default for HD installs? ;)

Have a look here.

Oh and BTW the proper way to add something to /etc/init.d is:

update-rc.d iptables defaults

Thanks for the tip. I'm scrounging the script file now, and learnign a lot about the nitty gritty of iptables.

Before, I didn't know you could hack the proc ip4 directory to stop loads of different icmp and spoof attacks...!