Quick question for enabling NAT in LTSP (or edubuntu) - iptables details

[Patrick McKnight]

Greetings,

I am creating a GPL script to enable NAT and have the script almost
done but have one minor question about iptables.  In the
ThinClientHowtoNAT, step 5 states that iptables needs to be updated
with the iptables append command.  When I do this, NAT works like a
charm.  I also use iptables-save and write the information to a file
(/etc/ltsp/nat) and use the same interfaces command used in the HOWTO
but it never comes back up on reboot.  While writing my script, I
noticed a difference between the HOWTO specs and my interfaces file.
I have my LTSP network on eth1 and so I used up iptables-restore <
/etc/ltsp/nat for eth1 and NOT eth0 as specified in the HOWTO.  That
got me thinking.  Is eth0 the proper interface to restore the iptables
setting or is eth1?  If it matters then I am confused.  My eth0 is my
NIC that goes to the internet; eth1 is my LTSP NIC.  Can anyone help
clear up my confusion if I am truly confused?

Thanks greatly in advance.

-- 
Cheers,

Patrick