bin bash IPTABLES sbin iptables VPN_IF ppp0 VPN_IP ifconfig VPN_IF awk

#!/bin/bash

IPTABLES="/sbin/iptables"
VPN_IF="ppp0"
VPN_IP=`ifconfig $VPN_IF | awk '/inet addr:/{sub("addr:", "", $2); print $2}'`

echo 1 > /proc/sys/net/ipv4/ip_forward

modprobe ip_tables
modprobe ipt_helper
modprobe ip_conntrack
modprobe ip_conntrack_ftp
modprobe ip_conntrack_irc
modprobe iptable_nat
modprobe ip_nat_ftp
modprobe ip_nat_irc
modprobe ip_gre
modprobe ip_nat_pptp

$IPTABLES -P INPUT ACCEPT
$IPTABLES -P OUTPUT ACCEPT
$IPTABLES -P FORWARD ACCEPT

$IPTABLES -F
$IPTABLES -X
$IPTABLES -t nat -F

$IPTABLES  -t nat -A POSTROUTING -s 192.168.0.0/24 --out-interface $VPN_IF -j SNAT --to-source $VPN_IP