Copying/routing from eth0 to eth1 and eth2

[theVOID]

Hi!

I have a question regarding using multiple network adapters in LINUX.

I want to take all data that comes in on eth0 and route that data out over eth1 and eth2.
The SAME data over both interfaces.

How can I accomplish this?
We have tried Iptables, TC, route etc and even looked at multilink PPP and multipath routing but all we can
get is some kind of balanxing that sends half of the data over one interface and the other half over another.

I want to route the same data out over two separate interfaces, for reduncandy.

Any tips on how to do this?

Many many thanks


Henrik

[newd to linux]

This may seem like a stupid question, but why would you want that? I can see absolutely no advantage or benefit to doing that.

[theVOID]

Hi!

I feel I need to explain in more detail why we want to do this

Basically , we are designing a product that enables a netwroked sensor that is connected by fiber or such today, to be connected via wireless 3G instead.

However as 3G is not that good todya, we wish to increase the uptime by using two parallel connections too two different ISP's.

So when I say copy from eth0 to eth1 and eth2 a, what we really do IS copying from eth0 (where the customers units is connected) and send this data over two 3G modems (configured as hso0 and hso1, the driver from phasrcape.)

This data is sent over two VPN tunnels to our server. Our server takes the data and forward it to the server the customers sensor wants to reach.

If one of the 3G ISP's have a problem, that is ok as we send over two ISPs at the same time..

We also need a way of labeling the packets so we can see that we dont duplicate data at our servers side.

This can be done with a function in IPTables.


We could of course do all this just with IP Socket programming on each device, but we want to try to do it with Linux standard stuff first!


So, that was thge whole deal Any ideas on how to route the same data from one interface out over two othes?

Best Regards

Henrik