First you need the "iptables-persistent" package. This gives you an init script that loads your settings from /etc/iptables/rules.v4 and rules.v6
When you install it, it wll save your default setings in /etc/iptables.
sudo apt-get install iptables-persistent
Remember that the rules are stored here:
For IPV4: /etc/iptables/rules.v4
For IPV6: /etc/iptables/r........