[SLUG] simple firewall

[Kevin Waterson <kevin@xxxxxxxxxxx>]

Howdy all, having a spot of bother with this fw
I would normally take this to the netfilter n00bs list
but cannot seem to get listed :/ anywho...
My goal is to have a simple masquerading script that will
deny all and forward all http traffic to 192.168.0.3
Sounds simple enough.. Here is what I have so far..

#!/bin/bash

# path to iptables
IPTABLES="/sbin/iptables"

# Then flush all rules
$IPTABLES -F
$IPTABLES -t nat -F

# masquerading stuff
$IPTABLES -t nat -A POSTROUTING -d ! 192.168.0.0/24 -j MASQUERADE

$IPTABLES -A FORWARD -s 192.168.0.0/24 -j ACCEPT
$IPTABLES -A FORWARD -d 192.168.0.0/24 -j ACCEPT
$IPTABLES -A FORWARD -s ! 192.168.0.0/24 -j DROP

# Turn on IP forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward

# send incoming ppp0 at port 80, to 192.168.1.18:80
$IPTABLES -t nat -A PREROUTING -i ppp0 -p tcp --dport 80  -j DNAT --to 192.168.0.3

# you must also open the port from outside in the firewall, like this:
$IPTABLES -A INPUT -p tcp --dport 80 -j ACCEPT


any thoughts or pointers greatfully recieved

Kind regards
Kevin
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Kevin Waterson
Port Macquarie, Australia