HOW TO : Modify iptables rules

Quick how to for my personal records. iptables is an open source firewall (and it does a lot more) included with most linux distributions.

Steps to add new rule to existing configuration

  • Check the list of rules and their corresponding sequence

[code]sudo iptables -vL –line-numbers [/code]

  • Add the new rule at the required location/sequence

[code] sudo iptables -I INPUT LINE_NUMBER RULE [/code]

Example :

[code]iptables -I INPUT 8 -s X.X.X.X/24 -p tcp -m state –state NEW -m tcp –dport 3128 -j ACCEPT[/code]

  • Save the configuration

[code] sudo serivce iptables save [/code]

Thx to Sijis for helping with the commands.