KVM Networking Hell

Jamie McDonald jmack at iclebyte.com
Wed Jun 9 13:57:45 UTC 2010


You are correct, I cannot ping the gateway from the guest - however I can
from the host.

The output of 'brctl show' on the host is as follows

## START brctl output ###

$brctl show
bridge name     bridge id               STP enabled     interfaces
br0             8000.001999705a61       no                  eth0

## END brctl output ##

>From looking at this it looks like I should have my guest configured to use
the vnet0 interface instead of br0?
Why when the testbox.xml VM configuration file is configured to use br0 is
vnet0 being created when I start the VM via virsh?

brtables has not been modified in any way.

Serge, thanks for your input but I can't really do a traceroute easily
because I can't connect this guest to the internet to download any packages
or dependancies for the tcptraceroute program.

It's really strange, the host and the guest communicate fine.

Any more ideas?

Kind Regards,

On Wed, Jun 9, 2010 at 12:26 PM, Soren Hansen <soren at ubuntu.com> wrote:

> On Wed, Jun 09, 2010 at 08:49:10AM +0100, Jamie McDonald wrote:
> > These changes have been enabled and I can still ssh between both the
> > host and the guest, but still no external conectivity for the guest.
> Just to be clear, you can't even ping e.g., right?
> Can you provide the output of "brctl show" on the host, please?
> I assume you haven't played with brtables or anything like that?
> --
> Soren Hansen
> Ubuntu Developer
> http://www.ubuntu.com/
> Version: GnuPG v1.4.10 (GNU/Linux)
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