Re: NET5501 and tcpdump problem

[christos%astron.com@localhost (Christos Zoulas)]

In article <F11287F1-6E7B-4EC6-838C-EBF645FD5D8B%eis.cs.tu-bs.de@localhost>,
J. Hannken-Illjes <hannken%eis.cs.tu-bs.de@localhost> wrote:
>On Nov 27, 2012, at 9:00 AM, Jukka Marin <jmarin%embedtronics.fi@localhost> 
>wrote:
>
>> Hi,
>> 
>> When I start "tcpdump -i vr0" on NET5501 / NetBSD 6.0, all incoming traffic
>> stops for 30 seconds and when I kill tcpdump it happens again.  Other
>> interfaces work normally during this time.  I got this in kernel log:
>> 
>> vr0: using force reset command.
>> 
>> On other vr interfaces, there's a similar effect, but it lasts only a few
>> seconds instead of 30.  Tcpdumping tun interfaces causes no problems.
>> 
>> A bug in the vr driver, perhaps?
>
>Most likely switching promiscuous mode on and off.  Some controllers
>have to re-negotiate the link.  Giving the `-p' flag to tcpdump disables
>promiscuous mode.

Yes, and most drivers can be fixed not to do that when the switch into
and out of promiscuous mode.

christos