network config bash file

#!/bin/sh
#
# internet connection sharing wlan0 is the gate way
# eth0 is the lan port this might use a straight ethernet cable to a router wan port or a switch or a single PC
# 192.168.2.2 is the port that is being used by the lan for access I changed it to 192.168.2.254 and set fixed addresses for the wan and router
#
# change wlan0 to ppp0 and you can use this for mobile broadband connection sharing
#
ip link set dev eth1 up
ip addr add 10.42.0.1/24 dev eth1
sysctl net.ipv4.ip_forward=1
iptables -t nat -A POSTROUTING -o ppp0 -s 10.42.0.0/24 -j MASQUERADE
iptables -t nat -A PREROUTING -i ppp0 -p tcp --dport 3074 -j DNAT --to-destination 10.42.0.2
iptables -t nat -A PREROUTING -i ppp0 -p udp -m multiport --dports 88,3074 -j DNAT --to-destination 10.42.0.2
iptables -A FORWARD -i ppp0 -d 10.42.0.2 -p tcp --dport 3074 -j ACCEPT
iptables -A FORWARD -i ppp0 -d 10.42.0.2 -p udp -m multiport --dports 88,3074 -j ACCEPT