Where are default iptable rules?

[egeex]

Hello,

1st attempt with unbutu.
i have installed server 8.04 and have it up and running. i am trying to configure new default iptable rules and having difficulty. I have created my rules saved them to a file and modified the /etc/network/interfaces as suggested here https://help.ubuntu.com/community/IptablesHowTo. when i reboot or restart networking I get no address on my eth0 interface and no routes at all. all networking down. when i remove my changes and reboot/restart networking eth0 is back to normal, routes are present and iptables has a new set of rules. where are these rules coming from and how can i modify them.

any suggestions are appreciated

regards
mjs

[nixscripter]

What exact changes have you made? Post /etc/iptables.rules and /etc/network/interfaces (before and after your modifications).