Il 14/05/2020 20:13, Strahil Nikolov ha scritto:
> On May 14, 2020 6:16:06 PM GMT+03:00, Stefano Danzi <s.danzi@hawai.it> wrote:
>>
>> Il 14/05/2020 12:50, Dominik Holler ha scritto:
>>>
>>> On Wed, May 13, 2020 at 9:44 PM s.danzi <s.danzi@hawai.it
>>> <mailto:s.danzi@hawai.it>> wrote:
>>>
>>>      Hi to all!
>>>
>>>      I'm having an issue with networks bridges on ovirt node.
>>>
>>>      It's look like this bug:
>>>      https://bugzilla.redhat.com/show_bug.cgi?id=1279161
>>>
>>>      On VM I have a bridge between a tap device and network
>> interface.
>>>      On node side the interface is bridged with bond0 vlan 128
>>>      (bond0.128 lacp).
>>>
>>>      When I ping an host on the other side of tap device I can see
>> this:
>>>      Arp request goes from my lan to the tap device on vm. Arp reply
>>>      return from tap vm and bridge forward this to vm networks
>>>      interface. Using tcpdump on vm interface on node I can see the
>> arp
>>>      reply, using tcpdump on bond0.128 or on bridge I can't see the
>> arp
>>>      reply.  Arp request is forwarded from bond0.128 to vm net but arp
>>>      reply isn't forwarded from vm net to bond0.128.
>>>
>>>
>>>
>>> Any chance that there is network filtering involved?
>>> Please check if the related vNIC profile has No Network Filter.
>>> If there is a Network Filter set, please shutdown the VM, set to No
>>> Network Filter in the vNIC profile, and start the VM again and check
>>> if the issue is gone.
>> Hi! No Network filter.... It was my first check.

> Have you checked the MTU ?
> You need to keep it a little bit lower on the VM, as you have vlan on the hypervisor.
>
> Best Regards,
> Strahil Nikolov
Hi! I have to check, but it is strange.....
Arp replies originated from the VM has not problems, only ARP replies
that came from TAP device in VM where not forwarded to real LAN.

Exactly as descived in bz1279161 (that's solved in bz1135347 but it's
not public and I can't read it)