Re: [Qemu-devel] Networking possibilities

[Jim C. Brown]

On Mon, Dec 27, 2004 at 08:26:56PM +0800, Ming-Ching Tiew wrote:
> 
> I would like to know if it is possible to run a few instances
> of Qemu's ( ie a few guest OS'es ) and make them network 
> with one another ? In each of the instance there maybe 
> multiple network cards, I would like to be able to specify each 
> network card to go to which tun device and then allow another 
> instance to connect specifically to that particular tun device,
> instead of only connected to the host OS.

You don't need multiple tuntap devices in the guest, you only need one.

> 
> That's tun/tap devices are used to connect multiple instances
> of qemu together or with the host OS.

There are two ways I can think of to do this.

The easy way is to use VDE (vde.sourceforge.net), which allows you to share a
single tuntap device amoung all qemu instances. (Or, if you don't have root
permissions, it can even emulate a tuntap device for you). The VDE HOWTO should
give the basics on how to do this.

The hard way is to set up each qemu instance normally, and then connect them
together thru the host, either with bridging or iptable tricks.

> 
> Bottomline I would like to be able to set up a farm of guest OS's
> which could perform internetworking among each other. This is
> extremely useful for testing/developing networking software. 
> Is it possible ?

Yes.

> 
> Cheers


-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.