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-ch... TLDR; turn off TCP IPv6 Checksum Offload Affects all operating systems (Windows, BSD, Linux, etc) using the affected wired Intel ethernet controllers. Not a problem with Intel WiFi.