libvirt users - Oct 2017 - Re: net interface direct - no IP communication between guest & host

hi everyone

I wonder why, when I attach an interface like this:

virsh # attach-interface --domain win10Ent --type direct 
--source nm-team --config --persistent --model virtio

host cannot ip ping the guest and vice versa, yet guest can 
ping other nodes(outside of its host, connected via phys net 
via a switch)

Would you know?

I thought maybe routing on the host, so I did:
$ route add -host 192.168.2.222 dev nm-team

but to no avail.

I wonder if it's lower layer, arp kernel bits?

thanks, L.

On Tue, Oct 24, 2017 at 03:52:52PM +0100, lejeczek
wrote:
> hi everyone
> 
> I wonder why, when I attach an interface like this:
> 
> virsh # attach-interface --domain win10Ent --type direct --source nm-team
> --config --persistent --model virtio
> 
> host cannot ip ping the guest and vice versa, yet guest can ping other
> nodes(outside of its host, connected via phys net via a switch)
> 
> Would you know?
> 
> I thought maybe routing on the host, so I did:
> $ route add -host 192.168.2.222 dev nm-team
> 
> but to no avail.
> 
> I wonder if it's lower layer, arp kernel bits?
I expect you'll be hitting this unfortunate gotcha:

https://wiki.libvirt.org/page/TroubleshootMacvtapHostFail

Regards,
Daniel
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On 25/10/17 08:05, Daniel P. Berrange wrote:
> On Tue, Oct 24, 2017 at 03:52:52PM +0100, lejeczek wrote:
>> hi everyone
>>
>> I wonder why, when I attach an interface like this:
>>
>> virsh # attach-interface --domain win10Ent --type direct --source
nm-team
>> --config --persistent --model virtio
>>
>> host cannot ip ping the guest and vice versa, yet guest can ping other
>> nodes(outside of its host, connected via phys net via a switch)
>>
>> Would you know?
>>
>> I thought maybe routing on the host, so I did:
>> $ route add -host 192.168.2.222 dev nm-team
>>
>> but to no avail.
>>
>> I wonder if it's lower layer, arp kernel bits?
> I expect you'll be hitting this unfortunate gotcha:
>
> https://wiki.libvirt.org/page/TroubleshootMacvtapHostFail
really nice pointer, thanks.
So I changed some bits, NIC for quest now is:

vnet2      bridge     192-168-2-0 virtio

and network is:

<network>
   <name>192-168-2-0</name>
   <uuid>4e03af62</uuid>
   <forward mode='bridge'/>
   <bridge name='nm-bridge1'/>
</network>

and the host's bridge(nm-bridge1) comprise of one net-team 
device which builds on two phys NICs.
And... the problem remains the same - other hosts/node(via a 
switch to which nm-team is connected) can get to the quest 
but the host itself cannot(and vice versa)
So no "macvtap" but still does not work.

>
> Regards,
> Daniel