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[Vishvananda Ishaya <vishvananda@xxxxxxxxx>]

Strange, I haven't seen this.  It sounds like maybe you have a mac address conflict somehow.  The only time I've seen duplicate icmp responses is when I was running inside of virtualbox and due to the way vagrant was setting up vms, I had multiple vms with same mac.

Vish

On Oct 14, 2011, at 5:59 AM, Shyam Kaushik wrote:

> Hi Vish,
>  
> In our openstack deployment we observe this:
>  
> Since linux_net.py/initialize_gateway_device() does this
>     # NOTE(vish): If the public interface is the same as the
>     #             bridge, then the bridge has to be in promiscuous
>     #             to forward packets properly.
>     if(FLAGS.public_interface == dev):
>         _execute('ip', 'link', 'set',
>                      'dev', dev, 'promisc', 'on', run_as_root=True)
>  
>  
> Any VM spawned on the cloud controller node if it sends an ICMP ping to an external network gets duplicate replies (i.e. there are 2 replies for the same ICMP request). For VM’s spawned on any other non-cloud controller this doesn’t happen.
>  
> If we turn of promiscus mode on the bridge, the VM on cloud controller doesn’t see the duplicate replies, but VM’s on non-cloud controller cannot reach external network.
>  
> Question to you is, is this duplicate ICMP replies expected for VM’s running on cloud controller due to above logic?
>  
> --Shyam
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