robotnet.sh

#!/bin/bash

# Echo commands and abort on errors
set -x
set -e

# Define network interfaces:
IFACE_WAN=wlan0
IFACE_LAN=eth0

# Clean
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT
iptables -F
iptables -t nat -F

# Do masquerade
iptables -A FORWARD -i $IFACE_WAN -o $IFACE_LAN -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -i $IFACE_LAN -o $IFACE_WAN -j ACCEPT
iptables -t nat -A POSTROUTING -o $IFACE_WAN -j MASQUERADE

# Enable packet forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward

# Allow DNS requests from LAN
iptables -A INPUT -p udp -i $IFACE_LAN --dport 53 -j ACCEPT