I am trying to find a way to determine whether or not I have any packets with VLAN headers flowing on my network by using something like WireShark. My understanding is that the default behavior for most Linux network drivers is to strip the VLAN headers below the level where the packet tracing hooks are.

So, is there any chance that the network drivers for BackTrack (especially tg3) have been configured to surface the VLAN headers intact for capture by tcpdump/WireShark, or whether there is a documented procedure for turning this capability on?