[libvirt-users] Guests can't connect to each other

[Laine Stump]

On 04/16/2012 07:02 AM, Anthony Bourguignon wrote:
> Le dimanche 15 avril 2012 à 10:19 -0400, Laine Stump a écrit :
>> Your config looks fine (the important part is that you're using bridge
>> mode for macvatap rather than private). I would suspect some sort of bug
>> related to using macvtap on a vlan device (or, even more, a vlan
>> connected to a bond). Try changing your network config to use
>> 1) a vlan connected directly to eth0 or eth1, rather than the bond, 2)
>> bond0 directly, and 3) eth0 or eth1 directly. This will hopefully give
>> you an idea of which part of the equation isn't working.
> I've just tested with a vlan directly connected to eth0 (1) and eth0
> directly (3) and I've still got the same behavior. That's really
> strange.

So if you define a network like the following, and connect the guests to
it, the guests can all communicate with the outside world, but not with
each other:

<network>
  <name>eth0-direct</name>
  <forward dev='eth0' mode='bridge'>
    <interface dev='eth0'/>
  </forward>
</network>


This would lead me to believe a problem in your kernel's macvtap
"bridge" mode - it really sounds like it's insisting on using "private"
mode instead. I'm not conversant on what macvtap bugs were fixed in what
kernel version, but you could start by looking to see if there's a later
version you could easily upgrade to.