em, vlan and pf troubles

[Max Laier]

On Tuesday 30 November 2004 22:17, Mike Wolman wrote:
> Hi,
>
> I am having a problem with 5.3 release with pf, vlans and the em device.
<...>
> I have had a hunt on the lists and found:
>
> http://marc.theaimsgroup.com/?l=freebsd-net&m=110172867801777&w=2

From what I know about this problem, it is possible that trying to analyze to 
problem creates the problem in the first place. i.e. if you tcpdump on the 
em-card (or the vlan for the same reason) it will screw up the vlan hardware 
support. A fix has been committed, but it might be the case that the fix 
wasn't 100% correct (esp. when there are 3+ vlans on the interface).

Is is possible that you switched to dhcp for these boxes? If you run dhclient 
on em0 it will open a bpf-socket which seems to be the root of the em+vlan 
troubles. I doubt that pf plays a part in this game.

> I am not sure if this is related but suspect it is - if so will adding a
> different card from a different vendor fix this? (the machine is at a
> remote location but if this will fix the problem off i go)

Using a card w/o hardware supported vlan tagging might help, but you obviously 
lose the benefit. I am not sure if you can turn off the h/w-support on the 
em-card, but that's sure worth a try. Tell us if it helpped.

-- 
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