dhcpcd hook to restart shorewall whenever the IP address changes (put in /lib/dhcpcd/dhcpcd-hooks)

90-restart_shorewall

if [ "$interface" = eth1 ]; then
  if [ "$if_up" = true ]; then
        IP=`ip add show eth1|grep global |awk '{print $2}'`
        PREVIOUS_IP=`cat /tmp/previous_ip`
        if [ "$PREVIOUS_IP" != "$IP" ]; then
          echo "$IP" > /tmp/previous_ip
          systemctl restart shorewall.service
        fi
  fi
fi