setting promisc mode kills vlans on devices with hwtagging (em, re ...)

[Robert Watson]

On Tue, 23 Nov 2004, Iasen Kostov wrote:

> if you setup a vlan devices with parent one of emX or reX (this what I
> have at the moment)  which has hardware vlan tagging just try to run
> tcpdump (without -p) and the vlans will die :). That doesn't happen with
> parent devices not supporting hwtagging. And this totally excludes
> possibility to run a bridge over vlans with parent device which support
> hwtaggs.  And something else was observed with re driver - it is
> impossible to disable hwtaggs by -vlanhwtag neither you can disable vlan
> mtu :).

I recently fixed this bug in if_em in HEAD, and will be merging that back
to RELENG_5 shortly.  We plan to also merge the change to RELENG_5_3 as an
errata patch fix.  It does not surprise me that if_re has a similar bug;
I'll look at abstracting the solution in the next few days.

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Principal Research Scientist, McAfee Research