#!/bin/sh
set -e

IPT=/sbin/iptables

[ "$IFACE" != "lo" ] || exit 0

# forwarding deaktivieren
echo 0 > /proc/sys/net/ipv4/ip_forward

# Default-Policies setzen
$IPT -P INPUT DROP
$IPT -P FORWARD DROP
$IPT -P OUTPUT ACCEPT

# loopback freischalten
$IPT -A INPUT -i lo -j ACCEPT
$IPT -A OUTPUT -o lo -j ACCEPT


# Antworten auf bestehende Verbindungen erlauben
$IPT -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT