10.5. Flushing the Ruleset

One last command that might be useful allows you to flush all the IP accounting rules you have configured. This is most useful when you want to radically alter your ruleset without rebooting the machine.

The -f argument in combination with the ipfwadm command will flush all of the rules of the type you specify. ipchains supports the -F argument, which does the same:
# ipfwadm -A -f
# ipchains -F
# iptables -F
This flushes all of your configured IP accounting rules, removing them all and saving you having to remove each of them individually. Note that flushing the rules with ipchains does not cause any user-defined chains to be removed, only the rules within them.