#!/bin/sh
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
echo 0 > /proc/sys/net/ipv4/conf/all/accept_source_route
echo 0 > /proc/sys/net/ipv4/conf/all/accept_redirects
echo 0 > /proc/sys/net/ipv4/conf/all/send_redirects
echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
echo 1 > /proc/sys/net/ipv4/conf/all/log_martians
echo 2 > /proc/sys/net/ipv4/ip_dynaddr
echo 0 > /proc/sys/net/ipv4/tcp_ecn

iptables -P INPUT   DROP
iptables -P FORWARD DROP
iptables -P OUTPUT  DROP

iptables -F
iptables -X
iptables -Z

iptables -A INPUT  -i lo -j ACCEPT
iptables -A OUTPUT -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT