[Fedora-xen] Dom0 running dhcpd and domU dhclient won't work on the same machine

[Roberto Fichera]

On 03/04/2011 06:36 PM, Roberto Fichera wrote:
> On 03/04/2011 05:17 PM, Marko Ristola wrote:
>> 04.03.2011 14:16, Roberto Fichera kirjoitti:
>>> Hi All,
>>>
>>> does anyone has the same problem on the same configuration?
>>> Basically all the domU aren't able to get their ip address from the DHCPD
>>> server running under the same dom0 with kernel 2.6.32.26-174.xendom0.fc12.x86_64.
>>> I tried different domU kernels but it seems doesn't work at all.
>>>
>>> Any idea how to solve it?
>>>
>>> Thanks in advance.
>>> Roberto Fichera.
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>> It should be solvable by configuring.
>>
>> I use bridge device br0, a remote dnsmasq server for DHCP and DNS. sysctl.conf is
>> configured so that br0 works as expected: passes DHCP requests thrue.
>>
>> Your case is different than mine, so you need different configurations.
>>
>> Googling examples is a good start.
>> You could try to use iptables LOG rules to track down problems.
> I mean, it seems working because the dhcpd log shows that the requests
> are coming from the domU but the domU doesn't get the DHCPD answare.
>
> I also read about setting off ethernet tx offload under dom0 via "ethtool -K eth0 tx off"
> but it seems not helping to solve anything, at least in my case.
>
> Which kind of configuration you made in your side?

I was just able to solve it right now!!! What I do is the ethtool setup like above in dom0
than afterwards I made a service dhcpd restart and it worked fine at the price of loosing the
tx offload automatically made by the network card.

>> Regards,
>> Marko Ristola
>>
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