[poky] QEMU networking

Mark Hatle mark.hatle at windriver.com
Thu May 12 09:32:51 PDT 2011


On 5/12/11 11:28 AM, Gary Thomas wrote:
> On 05/12/2011 10:23 AM, Mark Hatle wrote:
>> I had the same problem on my Fedora host.  It turned out that the iptables rules
>> were prohibiting the forwarding of packets from one network to another, causing
>> the route to the internet to black hole.
>>
>> Check that you don't have any IP tables that are preventing the routing from
>> working.
> 
> I don't have any tables that would cause this on my box other than what is
> set up by runqemu (it adds some NAT/MASQUERADE rules).  I have the same behaviour
> on Fedora and Ubuntu hosts.
> 
> That said, it's the configuration on the target that's causing problems.
> I don't know what's getting in there and changing the routing periodically.

Ahh, sorry, my reading comprehension has gone away today.

Check if you have a dhcp client running on the target side.  It's possible that
it keeps requesting updates and there is a bug (or "feature") in the client that
resets your routes automatically?

--Mark

>> On 5/12/11 11:10 AM, Gary Thomas wrote:
>>> I'm having a devil of a time getting networking to work when
>>> I run qemu (a Poky derived image, of course!)  I'm running this
>>> on a box which itself is NAT'd to the real internet, like this:
>>>
>>>      +-------------+        +------------------+
>>>      |   QEMUarm   |<------>|   My_Desktop     |<---->  Internet
>>>      | 192.168.7.2 |        |   192.168.7.1    |
>>>      +-------------+        |   192.168.1.125  |
>>>                             +------------------+
>>>
>>> Firstly, something is messing with the routing tables over time
>>> and I can't get past the first hop.  If I reconfigure the network
>>> on the QEMU system like this:
>>>     # ifconfig eth0 down
>>>     # ifconfig eth0 up
>>>     # route add default gw 192.168.7.1
>>> I can then access past "My_Desktop", e.g.
>>>     # ping 192.168.1.101
>>>        -or-
>>>     # ping 74.125.225.19    (www.google.com)
>>> This works fine and the routing table (route.good) is correct.
>>>
>>> A little while later (minutes), the routing changes and now I can't
>>> get past 'My_Desktop' (i.e. I can ping 192.168.1.125, but not 192.168.1.101)
>>> The routing table has changed (route.bad)
>>>
>>> What causes this?  I don't have avahi running anywhere and I've explicitly
>>> disabled that daemon on the QEMU system.
>>>
>>> Finally, there seems to be no name resolution - /etc/resolv.conf comes
>>> up as:
>>>     nameserver 127.0.0.1
>>> If I want to resolve any real names, I have to update it manually.
>>>
>>> Note: I'm running core-image-sato with web-webkit added using zypper.
>>>
>>> Are others actually using the network with QEMU images?  like this?
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> poky mailing list
>>> poky at yoctoproject.org
>>> https://lists.yoctoproject.org/listinfo/poky
>>
>> _______________________________________________
>> poky mailing list
>> poky at yoctoproject.org
>> https://lists.yoctoproject.org/listinfo/poky
> 




More information about the poky mailing list