VZ FIOS and Intel TCP IPv6 Checksum Offload problems

William Herrin bill at herrin.us
Sun Aug 28 02:16:04 UTC 2022

On Sat, Aug 27, 2022 at 12:00 PM Sean Donelan <sean at donelan.com> 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.

Hi Sean,

Do you happen to have any details on the bug? I note that the IPv6
header DOES NOT HAVE a checksum; it relies on the checksum in the
layer-2 frame. I'm not clear how you "append" bytes to the ethernet
frame "after" calculating the checksum, have the hardware checksum
fail but have the software checksum succeed.

Bill Herrin

For hire. https://bill.herrin.us/resume/

More information about the NANOG mailing list