TCP checksum errors

Dazed_75 lthielster at gmail.com
Fri Apr 21 17:22:16 MST 2006


I had this experience and on researching it learned that the drivers
for gigabit ethernet setups defer the checksum calculation to
hardware.  So when your software tells it to send a packet, the driver
does not compute the checksum, the chip does.  Problem is that when
you use a capture utility like ethereal it sees the packet before the
chip does and reports the error.  That is why it is "normal" to see
this.

I would believe that netstat queries the hardware and that is why the
hardware reports no errors.

On 4/21/06, Tony Wasson <ajwasson at gmail.com> wrote:
> On 4/21/06, Shawn Badger <sbadger at cskauto.com> wrote:
> > I am seeing TCP checksum errors on one of my servers via Ethereal. I
> > have Googled looking for ways diagnose and correct the problem, but I
> > have found none. I checked with  "netstat -a -i eth0" and saw no RX
> > errors, so I am left to wonder if it is the network, the multiple
> > servers I get the errors from or the server I am monitoring. So I am
> > hoping someone out there can point me in the right direction.
> >
>
> If you are doing your packet capture from your server, this is normal.
> http://www.ethereal.com/faq.html#q11.1
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