nanog mailing list archives
VZ FIOS and Intel TCP IPv6 Checksum Offload problems
From: Sean Donelan <sean () donelan com>
Date: Sat, 27 Aug 2022 15:00:41 -0400 (EDT)
Hopefully, my pain will help someone else.I've had sporadic Internet slowdowns and stuck networking since IPv6 was enabled on my FIOS ONT a few months ago.
After too much troubleshooting, I found out some older Intel GbE ethernet cards have a IPv6 Checksum Offload incompatibility with certain fiber ONT terminals. As Verizon is enabling IPv6 on its FIOS network, you might find intermittent network problems.
Intermittent are the worst kind of problems.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.
Intel published an alert in 2017, but I didn't have IPv6 on FIOS then. https://www.intel.com/content/www/us/en/download/19174/disabling-tcp-ipv6-checksum-offload-capability-with-intel-1-10-gbe-controllers.html TLDR; turn off TCP IPv6 Checksum OffloadAffects all operating systems (Windows, BSD, Linux, etc) using the affected wired Intel ethernet controllers. Not a problem with Intel WiFi.
Current thread:
- VZ FIOS and Intel TCP IPv6 Checksum Offload problems Sean Donelan (Aug 27)
- Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems Michael Thomas (Aug 27)
- Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems Mel Beckman (Aug 27)
- Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems Michael Thomas (Aug 27)
- Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems Sean Donelan (Aug 29)
- Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems Christopher Morrow (Aug 29)
- Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems Brie (Aug 29)
- Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems Niels Bakker (Aug 29)
- Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems Mel Beckman (Aug 27)
- Re: VZ FIOS and Intel TCP IPv6 Checksum Offload problems Michael Thomas (Aug 27)