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Date: Thu, 24 Feb 2011 07:49:01 +0100 (CET)
From: Gerhard Wiesinger <lists@wiesinger.com>
Subject: Re: [Qemu-devel] Re: Network bridging without adding bridge with
	brctl, possible?
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: qemu-devel@nongnu.org, Arnd Bergmann <arnd@arndb.de>

On Wed, 23 Feb 2011, Jan Kiszka wrote:
> Right, but if I set IP(eth0) == IP(macvlan0), I'm able to communicate
> between macvlan0 and mactapX, thus between guest and host. Just
> re-checked here, still works (after resolving the usual MAC address mess
> I caused by configuring manually).

Thnx for the tipp.

Did you use MAC(eth0) == MAC(macvlan0) or MAC(eth0) <> MAC(macvlan0) to 
get it to work?

OK, that should be possible because of the layer2 "split brain" 
implementation of macvlan/macvtap between lower interface (e.g. eth0) and 
mavlan*/macvtap*. Therefore the macvlan*/macvtap* interfaces see only each 
other and the outer world/eth0 is another distinct layer2 domain.

My only concern is about layer3 (IP) and same IP address on the same host. 
Because of the "split brain" there shouldn't be any problem from the 
macvlan*/macvtap* point of view and also from the eth0 outside world view.

But from the view of "localhost"/iptables/routing the kernel sees 2 
identical IP addresses. Which one is used on a local ping or local 
connect?

I will try it out, too.

Ciao,
Gerhard

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