User:Jebba/NAT

NAT

This is a micro HOWTO, perhaps someday to be longer about how to turn your N900 into a wifi hotspot. In other words, you connect to the Internet via the GPRS (telephone data) connection, then share your connection via wifi with everyone within reach.  :)

kernel

You will need a kernel with NAT modules. I have one available. See my installing my custom kernel to get a usable kernel if you don't feel like building one. The 2.6.28-omap1-jebba6 kernel is known to work (2.6.28-20094102.3+0m11).

iptables / iwconfig

You need iptables and iwconfig to use this script. Thankfully they are in the extras-devel repository:

apt-get install iptables wireless-tools

freemoe-nat

Create and run this script:

#!/bin/sh
# Run this script to share your Internet connection.
# Activate your gprs0 (fone data) connection with the GUI
# Then run this  :)

set -x

# insert masquerade module
sudo modprobe ipt_MASQUERADE

# flush old rules
sudo iptables -F
sudo iptables -t nat -F

sudo iptables -t nat -A POSTROUTING -o gprs0 -j MASQUERADE

# forward IPs
echo -n 1 | sudo tee /proc/sys/net/ipv4/ip_forward

sudo ifconfig wlan0 down
sudo iwconfig wlan0 mode ad-hoc
sudo ifconfig wlan0 up
sudo iwconfig wlan0 essid freemoe
sudo ifconfig wlan0 10.0.0.1 netmask 255.255.255.0 up

Set up Guests

Right now the above doesn't provide DHCP or DNS services, which means you have to set up a static IP and set up DNS in your clients. Just use a static IP from 10.0.0.2 to 10.0.0.254, use 8.8.8.8 for your DNS servers, and set your gateway to 10.0.0.1. You'll need to set your client in ad-hoc mode and use ESSID freemoe.