[vbox-dev] How should "promiscuous mode" work ?

Klaus Espenlaub klaus.espenlaub at oracle.com
Thu May 12 13:42:03 GMT 2011

On 12.05.2011 14:07, Alexey Eromenko wrote:
> Hello,
> Since the work on UDP Tunnel mode is now complete, we would like to
> know what the new "promiscuous mode" supposed to do ?

This affects the behavior of the virtual switch used by Internal 
Networking, Bridged and Host Only. The executive summary is that one can 
now make a VM's switch port receive traffic targeted for other VMs or 
even the host in addition to the normal traffic.

It probably needs some better name, because it is only indirectly 
related to promiscuous mode - if the VM's network adapter isn't in 
promiscuous mode we go back to normal switch behavior as the VM wouldn't 
see the extra packets anyway.

In general it's something 99% of the users should never touch or need, 
but can be handy in case an expert wants to diagnose the cause of 
certain network problems.

> Isn't it a feature of guest network drivers ?

Nope. See above.

> <para>GUI: added setting for the promiscuous mode policy for
>            internal networks, bridged networks and host-only networks</para>

The functionality has been added to the API a while ago. Normal business.

> Which changes will be required for the UDP Tunnel patch, if any ?

None, as the UDP Tunnel transport doesn't go trough the virtual switch 
at all.


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