VZ FIOS and Intel TCP IPv6 Checksum Offload problems

Christopher Morrow morrowc.lists at gmail.com
Mon Aug 29 16:59:22 UTC 2022

On Mon, Aug 29, 2022 at 12:00 PM Sean Donelan <sean at donelan.com> wrote:
> On Sat, 27 Aug 2022, Michael Thomas wrote:
> >> In some situations where a client machine is connected via some specific
> >> Optical Network Terminals (ONTs), and data is appended after the packet
> >> checksum, the network adapter can drop receive packets when using TCP-IPv6
> >> Checksum Offload for receive traffic.
> >>
> >
> > My reaction is "offload from what"? Isn't this all done in silicon?
> Because the interoperability flaw is in silicon, it can't be easily fixed
> in either the legacy wired Intel ethernet controller or fiber ONT.  Would
> need to replace the hardware to fix the silicon.
> Need to disable the hardware IPv6 TCP checksum offload, so its not mangled
> or dropped at the silicon layers anymore.
> Its annoyingly intermittent and not visible with client-based Wireshark
> because the corruption occurs in the hardware controller.

Uhm, this includes various versions of the intel pro 1000 card... so
that's a TON of gear,
to include like lenovo laptops, for instance. I'd wager that this is
super common in the field.
The PDF in the download says;
  "Products Affected: All 1gbe and 10gbe intel ethernet controllers...."

One wonders if this is a case of the 'mac addresses that start with 4
or 6 fail' problem?
(the pdf has zero words about what the actual problem is)

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