ubuntu severだとiptablesが自動起動するようになっていない。
そこで/etc/init.d/配下にiptablesを作成し以下を記述。

参考URL:http://ubuntuforums.org/archive/index.php/t-19106.html

#!/bin/sh
#
#This  is a 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.

ENV="env -i LANG=C PATH=/usr/local/bin:/usr/bin:/bin"

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

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() {
        echo "Saving iptables state"
        iptables-save ${SAVE_RESTORE_OPTIONS} > ${IPTABLES_SAVE}
}

start(){
        checkrules || return 1
        echo "Loading iptables state and starting firewall"
        echo -n "Restoring iptables ruleset"
        start-stop-daemon --start --quiet --exec /sbin/iptables-restore -- ${SAVE_RESTORE_OPTIONS} < ${IPTABLES_SAVE}
}

case $1 in
        save)
                save
                echo "."
        ;;

        start)
                start
                echo  "."
        ;;

        stop)
                if [ "${SAVE_ON_STOP}" = "yes" ]; then
                        save || exit  1
                fi
                echo -n "Stopping firewall"

                for a in `cat /proc/net/ip_tables_names`; do
                        iptables -F -t $a
                        iptables -X -t $a

                        if [ $a = "nat" ]; then
                                iptables -t nat -P PREROUTING  ACCEPT
                                iptables -t nat -P POSTROUTING ACCEPT
                                iptables -t nat -P OUTPUT ACCEPT
                        elif [ $a = "mangle" ]; then
                                iptables -t mangle -P  PREROUTING ACCEPT
                                iptables -t mangle -P INPUT ACCEPT
                                iptables  -t mangle -P FORWARD ACCEPT
                                iptables -t mangle -P OUTPUT  ACCEPT
                                iptables -t mangle -P POSTROUTING ACCEPT
                        elif [ $a = "filter" ]; then
                                iptables -t filter -P INPUT ACCEPT
                                iptables -t filter  -P FORWARD ACCEPT
                                iptables -t filter -P OUTPUT  ACCEPT
                        fi
                done
                start-stop-daemon --stop --quiet --pidfile /var/run/iptables.pid --exec iptables
                echo  "."
        ;;

        restart)
                echo -n "Flushing firewall"
                for a in `cat /proc/net/ip_tables_names`; do
                        iptables -F -t $a
                        iptables -X  -t $a
                done;
                start
                echo "."
        ;;

        status)
                iptables -L
        ;;

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

exit 0

そして

sudo  update-rc.d iptables start 37 S . stop 37 0  .

として自動起動するようにする。