Re: Xen - port mirroring - Open vSwitch?

[Johan Ihrén <johani%johani.org@localhost>]

Hi,

On Nov 6, 2012, at 21:02 , Manuel Bouyer wrote:

> On Tue, Nov 06, 2012 at 07:16:28PM +0100, Johan Ihrén wrote:
>> I need to do port mirroring to capture traffic between DOMUs. Or, rather, I 
>> need to be able to capture the traffic somehow, be it port mirroring or 
>> something else.
>> 
>> As far as I can tell the NetBSD bridge device has no support for this. 
> 
> And it's not really needed: the traffic you want is present on at last
> one ethernet interface (virtual or real) as the traffic accross the
> bridge has to come from somewhere (and eventually goes somewhere).
> So just run tcpdump on the right interface. To capture a domU traffic,
> run tcpdump on the corresponding xvifx-y interface in dom0.

Hmm. Ok. I should really have thought about that.

I need to rethink this a bit, as what I thought I was really looking for was 
how to be able to model a physical setup with a corresponding virtual setup 
(i.e. I was looking for a DOMU to act as the tcpdumper thingy). Having the DOM0 
do the tcpdumping breaks the standard advice of leaving the DOM0 alone and do 
all work on the DOMUs, but perhaps in this case it is a reasonable compromise 
(although I've always hated those interface names that can not be predicted).

Another potential issue is that I cannot duplicate the tcpdumper machine, as it 
has to be the DOM0.

But I'll think about it. Thanks.

Johan