Re: QEMU networking

[Gary Thomas <gary@mlbassoc.com>]

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.

> 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?
>>
>>
>>
>>
>> _______________________________________________
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>> poky@yoctoproject.org
>> https://lists.yoctoproject.org/listinfo/poky
>
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-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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