[libvirt-users] bridge / ubuntu / no arp reply

[Michal Privoznik]

On 25.02.2014 22:45, François Chenais wrote:
> Hello
>
> I'm trying to setup a bridged guest on an ubuntu 13.10 but it doesn't work.
>
> (Everything is ok with NAT)
>
> Network sniffing shows that arp replies don't come back to the guest.
>
>
> Test 1
> ------
>
> Guest : ping host_bridge_ip   (ok)
>
>
>
> Test 2
> ------
>
> Guest: ping other_lan_host (KO)
>
>       other_lan_host
>
>              - receives arp who-is request
>              - sends arp reply
>              - arp -a   shows the guest macaddr
>
>
>       => Guest doesn't receive reply
>
>
> Test 3
> ------
>
> other_lan_host ping the Guest   (KO)
>
>     - arp -a shows "incomplete" addr
>     - Guest receives nothing
>
>
> On Host
> -------
>
> network tcpdump on bridge or vnet interfaces shows request but no reply ...
>
>
> Thanks in advance for help or ideas
>
>
>      François
>

I suspect firewall. By my experience 99% of network issues is caused by 
firewall. Try flushing all tables and see if that helps.

Michal