Subject: Re: `ifconfig wm3 ip4csum` creates bad cksums via tcpdump
To: NetBSD Current Users <>
From: Peter Eisch <>
List: current-users
Date: 05/22/2007 11:33:43
On 5/22/07 11:24 AM, "Charlie Allom" <> wrote:

> On Tue, May 22, 2007 at 07:50:34AM +1000, Daniel Carosone wrote:
>> On Sat, May 19, 2007 at 07:17:43PM +0100, Charlie Allom wrote:
>>> % ifconfig wm3 tcp4csum udp4csum tso4 ip4csum
>>> [[wait 34 seconds! poor sockets ]]
>> That seems weird. Can you determine whether this is some kind of name
>> resolution problem for, say, 'tcp4sum', or really time spent waiting
>> in the driver to set the flags?
> other systems don't do it with different cards?
> would it matter how much traffic is flowing through it?
> does it link down - then link up? could be the cisco switch?

This looks like spanning-tree took your port down for 30 seconds after the
nic reset.  The nic will reset when you apply something like that as well as
if you do a tcpdump on that interface without the -p flag.  You can avoid
such things in the future if you enable the spanning-tree portfast option on
that interface, or just do it prior to bringing the interface up at boot