How to split a TCP connection into two?

[Bonilla]

Hello,

I'd like to run a Gentoo computer at home which would be connected to two DSL connections at the same time using two different Ethernet cards. Both DSL connections are limited to an upstream of 1 mbit. In addition to this computer, I have rented a Gentoo server which is connected to the internet with 100 mbits up- and downstream. Furthermore there is a Windows XP notebook which is "on the road" thus using different types of internet connections all the time. The Windows XP notebook and the Gentoo computer at home are connected to each other using OpenVPN: the computer at home is running the daemon software and the Windows XP client "on the road" is running the client software. The OpenVPN connection between the notebook and the home computer is in fact a single TCP connection initiated by the client notebook. The daemon software on the home computer is listening on a port of one of the two Ethernet devices.

Is there any piece of software that could be run on my fast 100 mbit Gentoo server to split an incoming TCP connection from my notebook into two, forward those two connections to both external IPs of my home computer (both Ethernet adapters/DSL-connections) which would then reconstruct the original TCP connection? Or is there even a way to do this without my 100 mbit Gentoo server as middleman?

The idea is to increase the bandwidth within the OpenVPN environment in order to let my notebook receive data from my home computer at a speed of 2 mbits instead of just 1 mbit.

I'd appreciate it if you could offer any advice on this somewhat tricky issue.

Thank you very much in advance,

Bobby

[RoundsToZero]

Look into ethernet bonding, under Network Device Support in the kernel (CONFIG_BONDING).

By the way, you should be running OpenVPN over UDP, not TCP. See here for why. It won't matter though, because ethernet bonding operates at a lower level below the transport layer.

Edit: Read /usr/src/linux/Documentation/networking/bonding.txt to see if this will work for you.

[Bonilla]

Thank you very much, I'll look into ethernet bonding!

There is a simple reason for me using TCP instead of UDP with OpenVPN: My notebook finds itsself sometimes in a network environment that doesn't allow UDP connections. And I simply don't want to have two different kinds of configurations. But thanks for the tip anyway.

Greets,

Bobby