Subject: Re: [PATCH 2/2] [e1000 VLAN] Disable vlan hw accel when promiscuous mode

From: "Kok, Auke" <[email-masked]>
Date: Mon, 12 Nov 2007 14:54:35 -0800

Chris Friesen wrote:
> David Miller wrote:
> 
>> When you select VLAN, you by definition are asking for non-VLAN
>> traffic to be elided.  It is like plugging the ethernet cable
>> into one switch or another.
> 
> For max functionality it seems like the raw eth device should show
> everything on the wire in promiscuous mode.
> 
> If we want to sniff only the traffic for a specific vlan, we can sniff
> the vlan device.

actually the impact can be quite negative, imagine doing a tcpdump on a 10gig
interface with vlan's enabled - all of a sudden you might accidentally flood the
system with a 100-fold increase in traffic and force the stack to dump all those
packets for you.

I'm still very reluctant about this patch, I think the current situation is OK for
everyone and offers everyone the possibility to do what they need, without hidden
consequences.

Auke

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