Re: guest MAC-address isolation

[Robert Rebstock <rebstock@scienceworks.com>]

Hello.
Thank you for your answer.

> ----- Original Message -----
> From: "Avi Kivity" <avi@redhat.com>
> To: "Robert Rebstock" <rebstock@scienceworks.com>
> Cc: kvm@vger.kernel.org
> Sent: Tuesday, August 17, 2010 11:36:41 AM
> Subject: Re: guest MAC-address isolation
> 
>   On 08/06/2010 08:09 PM, Robert Rebstock wrote:
> > Hello all,
> >
> > can anyone recommend a better way to achieve (guest agnostic) MAC-address
> > isolation in qemu/kvm then with user-mode networking?
> >
> > I have multiple guests requiring the same MAC-address, and user-mode/slirp
> > networking is quite slow.
> >
> 
> You can put the different guests on different bridges, and use IP 
> routing to connect the two bridges; or you can use ebtables to mangle 
> the MAC addresses.
> 

Could you possibly give me an example? Unfortunately my networking skills are not the best,
which is not to say that I don't try. The best I can do, after reading the
documentation I could find, is:

ebtables -t nat -A PREROUTING  -d 00:11:11:11:11:11 -j dnat --to-dest 00:01:23:45:67:89 --dnat-target ACCEPT
ebtables -t nat -A POSTROUTING -s 00:01:23:45:67:89 -j snat --to-src 00:11:11:11:11:11 --snat-arp --snat-target ACCEPT

but I can see no way to mangle multiple identical MACs so as to achieve layer-2
isolation for my snapshotted VMs.

Many thanks,

RR