How to save rules of the iptables?

iptables1

Question: I create the rules to iptables. But, when I restart the computer, the rules don’t work! How to save the rules on Ubuntu ?

Answer: After of the write the commands iptables, do:

 1. sudo su
 2. iptables-save > /etc/iptables.rules
 3. In /etc/network/if-pre-up.d/iptables,put:

 #!/bin/sh
 iptables-restore < /etc/iptables.rules
 exit 0

 4. After, in /etc/network/if-post-down.d/iptables,put:
 #!/bin/sh
 iptables-save -c > /etc/iptables.rules
 if [ -f /etc/iptables.rules ]; then
 iptables-restore < /etc/iptables.rules
 fi
 exit 0
 5. After, give permission to the scripts:
 sudo chmod +x /etc/network/if-post-down.d/iptables
 sudo chmod +x /etc/network/if-pre-up.d/iptables

Further Reading: https://help.ubuntu.com/community/IptablesHowTo#Saving_iptables