Linux Network Administratoramp;#039;s Guide (3rd Edition) [Electronic resources] نسخه متنی

8.5. Flushing the Rule Set

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

The iptables command supports the
-F argument, which flushes all the rules of the
type you specify:

# iptables -F

This flushes all of your configured rules (not just your accounting
rules), removing them all and saving you having to remove each of
them individually.