Install the Persistent Firewall Service
sudo apt-get update
sudo apt-get install iptables-persistent
Save your running iptable rules to a file
sudo iptables-save > /path/to/my/firewall-rule
Restore from saved rules immediately
sudo iptables-restore < /my/firewall-rule
Reload your iptable immediately for 10 seconds for testing
sudo iptables-apply -t 10 your_rules_file
Save your iptable permanently. Survives even after reboot
sudo invoke-rc.d iptables-persistent save