Actions

-R – replace – requires a parameter to tell it which rule to replace, e.g., iptables -R INPUT 4 -p 6 –sport 22 -m state –state NEW -j ACCEPT replaces the fourth rule of the filter table INPUT chain with a rule that allows new, stateful SSH sessions to be established
-L – list the rules of a chain – use the -v option for a more verbose listing, e.g., iptables -L FORWARD -v

-R – replace – requires a parameter to tell it which rule to replace, e.g., iptables -R INPUT 4 -p 6 –sport 22 -m state –state NEW -j ACCEPT replaces the fourth rule of the filter table INPUT chain with a rule that allows new, stateful SSH sessions to be established