em, vlan and pf troubles

[Mike Wolman]

Hi Max,

No dhcp stuff is running on this box as a client or server
on any interfaces.

I can confirm running tcpdump does "mess" vlan stuff up.

I am reluctant to try the updates as on: 
http://marc.theaimsgroup.com/?l=freebsd-net&m=110172867801777&w=2 as we 
have a lot more than 3 vlans and the box is in use.

However i am willing to give it a go if it helps, is it as simple as 
grabbing the latest cvs files from src/sys/dev/em/* and 
doing a make buildkernel or do other parts of the tree need updating?

Also i have had a look through the docs for the em driver but cannot
see how to disable the hardware vlan tagging - does anybody know of is 
this possible?

Mike.

On Wed, 1 Dec 2004, Max Laier wrote:

> 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.
>
> -- 
> /"\  Best regards,                      | mlaier at freebsd.org
> \ /  Max Laier                          | ICQ #67774661
> X   http://pf4freebsd.love2party.net/  | mlaier at EFnet
> / \  ASCII Ribbon Campaign              | Against HTML Mail and News
>