Sharing internet from wlan0 to eth0 which runs to an overo gumstick.

[garland3]

Hi,
I have an overo gumstick with Tobi board expansion that gives it an Ethernet jack. If I plug my overo directly into my router than everything works just great.

I bought a cross over cable and plugged it into the overo and into my ubuntu laptop. The laptop has a wireless interface wlan0 that I use to connect to the router.

I want to forward all the packets from the overo over the ubuntu laptops wlan0 interface to the router so that the overo still uses dhcp and gets its own IP address from the router. How do I do that?

I've tried reading the ubuntu forums and all over google, but every case seems different and a little confusing. I tried making a bridge using firestarter, but apparently you can't actually bridge from wlan to eth0.

I'm thankful for any help.

All the best,

Anthony G.

[Lazydog]

Ensure that FORWARD is turned on in Ubuntu. without this Ubuntu will not forward the packets.

[garland3]

If I do

$cat /proc/sys/net/ipv4/ip_forward
1

This seems to indicate that it is able to forward packets.

In network manager, I have the wireless set to "Automatic DHCP", and the eth0 set to "Shared To Other Computers".

Thanks for the help. What else should I try/do?

[nplusplus]

Well, since you're having to go at this as a layer three problem and have set ip_forward, roughly what remains is the following.

1) Set a static IP on eth0.
2) Set a static route on the router that points to the wlan0 interface of the laptop as the next hop for the eth0 network, or setup the laptop and the router to dynamically share routes (i.e. through RIPv2, OSPF, or ISIS).
3) Configure the laptop as a DHCP relay with the IP address of the DHCP server.
4) Configure your DHCP server to hand out addresses for the network on the other side of eth0. Configure a scope for the network. Configure your options (gateway, DNS servers).

It seems weird you wouldn't be able to bridge the interfaces. I would think linux bridging wouldn't care about the difference in the two kinds of encapsulation. I mean, most consumer grade wireless routers do that anyway.

N

[Lazydog]

If I do

$cat /proc/sys/net/ipv4/ip_forward
1

This seems to indicate that it is able to forward packets.

OK, how did you come to this conclusion? What number does it provide?

1=FORWARD
0=OFF

[garland3]

I bought a wifi dongle so that I can connect wirelessly to the router all the time from the overo. It works well. It doesn't really answer the questions I was having though.

[Lazydog]

Do you have a firewall up and running?
Is it masquerading the packets leaving wlan0?

[garland3]

Can you give me step by step instructions on what to do??

I'm not sure how to accomplish some of the steps given by nplusplus.

In step 1. Do I sent the ubuntu computer to have a static IP? or the overo?
Step 2. How do I set up the router of the laptop to dynamically share routes?
Step 3. How do I configure the laptop as a dhcp relay?
Step 4. I'm assuming I don't' have to change anything on the router to let it hand out dhcp addresses?

Anthony G.