Ubuntu rc.d iptables

#!/bin/sh
#
#This is an Ubuntu adapted iptables script from gentoo
#(http://www.gentoo.org) which was originally distributed
#under the terms of the GNU General Public License v2
#and was Copyrighted 1999-2004 by the Gentoo Foundation
#
#This adapted version was intended for and ad-hoc personal
#situation and as such no warranty is provided.

. /lib/lsb/init-functions

IPTABLES_SAVE="/etc/default/iptables-rules"
SAVE_RESTORE_OPTIONS="-c"

checkrules() {
if [ ! -f ${IPTABLES_SAVE} ]
then
echo "Not starting iptables. First create some rules then run"
echo "\"/etc/init.d/iptables save\""
return 1
fi
}

save() {
/sbin/iptables-save ${SAVE_RESTORE_OPTIONS} > ${IPTABLES_SAVE}
return $?
}

start(){
checkrules || return 1
/sbin/iptables-restore ${SAVE_RESTORE_OPTIONS} < ${IPTABLES_SAVE}
return $?
}

case "$1" in
save)
echo -n "Saving iptables state..."
save
if [ $? -eq 0 ] ; then
echo " ok"
else
echo " error !"
fi
;;

start)
log_begin_msg "Loading iptables state and starting firewall..."
start
log_end_msg $?
;;

stop)
log_begin_msg "Stopping firewall..."
for a in `cat /proc/net/ip_tables_names`; do
/sbin/iptables -F -t $a
/sbin/iptables -X -t $a

if [ $a == nat ]; then
/sbin/iptables -t nat -P PREROUTING ACCEPT
/sbin/iptables -t nat -P POSTROUTING ACCEPT
/sbin/iptables -t nat -P OUTPUT ACCEPT
elif [ $a == mangle ]; then
/sbin/iptables -t mangle -P PREROUTING ACCEPT
/sbin/iptables -t mangle -P INPUT ACCEPT
/sbin/iptables -t mangle -P FORWARD ACCEPT
/sbin/iptables -t mangle -P OUTPUT ACCEPT
/sbin/iptables -t mangle -P POSTROUTING ACCEPT
elif [ $a == filter ]; then
/sbin/iptables -t filter -P INPUT ACCEPT
/sbin/iptables -t filter -P FORWARD ACCEPT
/sbin/iptables -t filter -P OUTPUT ACCEPT
fi
done
log_end_msg 0
;;

restart)
log_begin_msg "Restarting firewall..."
for a in `cat /proc/net/ip_tables_names`; do
/sbin/iptables -F -t $a
/sbin/iptables -X -t $a
done;
start
log_end_msg $?
;;

*)
echo "Usage: /etc/init.d/iptables {start|stop|restart|save}" >&2
exit 1
;;
esac

exit 0