[libvirt-users] (no subject)

Daniel P. Berrange berrange at redhat.com
Tue Nov 16 17:00:03 UTC 2010

On Tue, Nov 16, 2010 at 11:51:25AM -0500, David M. Barlieb wrote:
> HI, I've just begun using libvirt as part of my KVM installation and
> have been having some confusion regarding networking of my virtual
> guests. I'm not sure if I should even be sending this to this mailing
> list and if not please let me know and if possible where I should be
> sending this inquiry.
> I understand I can setup a dedicated bridged interface for my guest. But
> as for the virbr interface which is the default, I'm a little confused
> about. When using this, does the guest os use the same ip as the host?
> If so, then how to packets get to the guest instead of the host. I would
> guess there's an alternate mac address for the guest interface and this
> is how it gets there but am not certain. Sorry if this seems like a
> simple question but I'm not very well versed in networking.

This page describes the two commonly used networking setups


The virbr0 you get by default is providing NAT forwarding. If you want
full bridging to the LAN, then you should probably follow the second 
set of instructions there, and ignore the virbr0 device

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