#!/bin/bash
# This script enables a computer to act as an internet service provider using a
# null modem

/usr/sbin/pppd ttyS0 115200 crtscts local passive persist nodetach 192.168.1.1:192.168.1.2
/usr/sbin/pppd ttyS0 115200 crtscts local passive persist nodetach
read
iptables -t filter -A FORWARD -d 0/0 -s 192.168.1.0/24 -o ppp0 -j ACCEPT
iptables -t filter -A FORWARD -d 192.168.1.0/24 -j ACCEPT
# internal
iptables -t filter -A INPUT -s 192.168.1.0/24 -d 0/0 -j ACCEPT
iptables -t filter -A OUTPUT -s 192.168.1.0/24 -d 0/0 -j ACCEPT