LeapFrog Pollux Platform: Internet Access

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This page includes steps that describe how to use routing on your host to enable your Didj to access to the wider Internet via the USB connection.

They have been tested in Ubuntu 8.04 Hardy Heron (2.6.24-26 kernel), and are based on similar instructions for other handheld devices.

Prerequisites

You have set up USB networking as per http://elinux.org/Didj_Networking_HOWTO

Configuring the Host

In this example, we assume that the host has an ethernet connection on eth0. (your own config may be different; for example, you may be using a Wifi adapter. In theory, aside from your LAN specific configuration, the steps outlined below should still work.)

For this example we establish the following assumptions:

The gateway between the local network and the Internet is 192.168.0.1

The host is connected to the gateway as 192.168.0.116 (assigned by DHCP on eth0)

The host is connected to the Didj as 192.168.2.1 (assigned statically to usb0 on host)

The Didj is connected to the host as 192.168.2.100 (assigned statically to usb0 on Didj)

Configure the host machine's /etc/network/interfaces file as follows:

auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
auto usb0
iface usb0 inet static
       address 192.168.2.1
       netmask 255.255.255.0
       up route add -net 192.168.2.0 netmask 255.255.255.0 dev usb0
       up echo 1 > /proc/sys/net/ipv4/ip_forward
       up iptables -P FORWARD ACCEPT
       up iptables -A POSTROUTING -t nat -j MASQUERADE -s 192.168.2.100
       down route del -net 192.168.2.0 netmask 255.255.255.0
       down echo 0 > /proc/sys/net/ipv4/ip_forward
       down iptables -t nat -F POSTROUTING

To apply these new settings:

On the Host:

sudo /etc/init.d/networking restart

(of course, rebooting the host will also work)


Configuring the Didj

If you are using a standard Didj configuration and you have not yet done so, rmmod the g_file_storage kernel module and insmod the g_ether/ko module. (see http://elinux.org/Didj_Networking_HOWTO#Installing_g_ether.ko)

With the USB cable connected to your host, configure an IP address on a different subnet from the rest of your LAN

On the Didj:

ifconfig usb0 192.168.2.100 netmask 255.255.255.0

Next, add a route from your Didj to the host (making it the gateway) using the ip address of the host's usb0 device.

On the Didj:

route add default gw 192.168.2.1 usb0

Finally, add nameservers to your Didj's /etc/resolv.conf file (you can add the lines from this example which uses the OpenDNS servers)

nameserver 208.67.222.222
nameserver 208.61.220.220


At this point, your Didj is connected to the outside world - and a ping or a wget to yahoo or google should work.


Todo

Routing packets from the gateway to the Didj.


References

http://wiki.openmoko.org/wiki/USB_Networking

http://wiki.openzaurus.org/HowTos/USB_Networking_Without_Bridging

Acknowledgments

Thanks to losinggeneration for useful input on this!