16.4. Storing iptables Information
Rules created with the iptables command are stored in
memory. If the system is restarted after setting up
iptables rules, they will be lost. In order for
netfilter rules to persist through system reboot, they need to be
saved. To do this, log in as root and type:
/sbin/service iptables save
This executes the iptables init script, which runs
the /sbin/iptables-save program and writes the
current iptables configuration to the
/etc/sysconfig/iptables. This file should only be
readable by root.
The next time the system boots, the iptables init
script will reapply the rules saved in
/etc/sysconfig/iptables by using the
While it is always a good idea to test a new iptables
rule before committing it to the
/etc/sysconfig/iptables file, it is possible to
copy iptables rules into this file from another
system's version of this file. This provides a quick way to distribute
sets of iptables rules to multiple machines.
If distributing the /etc/sysconfig/iptables file
to other machines, type /sbin/service iptables
restart for the new rules take effect.