firewall_panic.sh

#!/bin/bash

# esta ip es la de la terminal del sysadmin
ssh_src="192.168.1.145"
ssh_sport="0:65535"
ssh_dport="0:65535"

case "${1}" in
        on)
                echo -n $"Firewall: Modo Panic - bloqueo de todas las comunicaciones:"

                modprobe ip_tables

                tables=`cat /proc/net/ip_tables_names`
                for t in ${tables}
                do
                        iptables -t "${t}" -F
                        iptables -t "${t}" -X
                        iptables -t "${t}" -Z

                        # Find all default chains in this table.
                        chains=`iptables -t "${t}" -nL | grep "^Chain " | cut -d ' ' -f 2`
                        for c in ${chains}
                        do
                                iptables -t "${t}" -P "${c}" ACCEPT

                                if [ ! -z "${ssh_src}" ]
                                then
                                        iptables -t "${t}" -A "${c}" -p tcp -s "${ssh_src}" --sport "${ssh_sport}" --dport "${ssh_dport}" -m state --state ESTABLISHED -j ACCEPT
                                        iptables -t "${t}" -A "${c}" -p tcp -d "${ssh_src}" --dport "${ssh_sport}" --sport "${ssh_dport}" -m state --state ESTABLISHED -j ACCEPT
                                fi
                                iptables -t "${t}" -A "${c}" -j DROP

                        done
                done

                echo "Firewall: bloqueo todas las comunicaciones:"
                echo

                exit 0
        ;;

        off)
                echo -n $"Firewall: Limpieza de todas las reglas:"
                modprobe ip_tables
                tables=`cat /proc/net/ip_tables_names`
                for t in ${tables}
                do
                        iptables -t "${t}" -F
                        iptables -t "${t}" -X
                        iptables -t "${t}" -Z

                        chains=`iptables -t "${t}" -nL | grep "^Chain " | cut -d ' ' -f 2`
                        for c in ${chains}
                        do
                                iptables -t "${t}" -P "${c}" ACCEPT
                        done
                done
                echo -n $"Firewall: firewall OK:"
                echo

                exit 0
        ;;

        *)
                echo "on|off"
        ;;
esac