a few websites not working with LAN

My case is very strange. I talked to support for hours and no one has any clue. I so wish someone here will have any idea what's going on!

I have a gigabit Fios connection and quite a few devices - TVs, doorbells, laptops. I also have 2 stationary computers with the router though Ethernet cables.

Everything worked great for years... until a few weeks ago a few websites stopped - almost or completely - working.

It's mostly about Youtube and Flickr.

AND IT'S ONLY WHEN USING WIRED CONNECTION.

Picture this - I open my laptop, go to youtube.com, after 1 second the front page loaded. I click on a video thumbnail, 1, sometimes 2 seconds later the video plays.

I do the same on any of my stationary computers - the front page loads very slow, sometimes I see blank rectangles instead of video thumbnails. I click on any - nothing's happening for like a minute, and then either the video plays in the lowest possible resolution or the website displays message "no Internet connection".

When I ping it - it pings great, 6/7 ms.

In another tab I can browse lots of other websites and everything works smooth!

It's not the computer, it's not the browser, I have 2 computers and use 4 browsers. It's also not the router, I just had it replaced.

I plugged a wifi adapter to one of the stationary computers and it works flawlessly now. All TVs and other streaming devices - no problems at all.

All other websites, even very heavy on data like streaming sited - work great.

Youtube and Flickr - don't.

Any ideas??? Thanks!

Accepted answers

gs0b

Verizon is in the process of rolling out IPv6.

The Alcaltel GPON ONT Verizon uses generates IPv6 TCP packets with junk data appended after the checksum.

Intel Ethernet chips silently drop these packets if they have TCP checksum offload enabled, which is the default.

The result of all of this is any device with an Intel Ethernet chip suffers from poor connectivity when IPv6 is enabled by Verizon.

We can argue all day long about whose fault this is - Intel for dropping packets with extra data after the checksum, or Alcatel for generating bad packets, or Verizon for rolling out IPv6 knowing about these issues; but that won't fix the problem.

The fix is simple - go into the device driver for the Intel Ethernet port and disable IPv6 TCP checksum offload. The work will now be down in software by the device driver, which is able to ignore the extra data.

Here's the Intel notice on the issue:
https://www.intel.com/content/www/us/en/download/19174/disabling-tcp-ipv6-checksum-offload-capability-with-intel-1-10-gbe-controllers.html

You don't need to use the PowerShell script, it's just a switch in the device driver.

All comments

pacmusicman

Has Verizon recently implemented IPv6 service? 🤔

gs0b

Verizon is in the process of rolling out IPv6.

The Alcaltel GPON ONT Verizon uses generates IPv6 TCP packets with junk data appended after the checksum.

Intel Ethernet chips silently drop these packets if they have TCP checksum offload enabled, which is the default.

The result of all of this is any device with an Intel Ethernet chip suffers from poor connectivity when IPv6 is enabled by Verizon.

Adaminion

Thank you soooooooo much! It would be great if Verizon support learned that solution. I wasted 2 hours on the phone and the guy kept trying to convince me this was happening because I have too many tabs opened............😀

gs0b

@Adaminion wrote:
Thank you soooooooo much! It would be great if Verizon support learned that solution. I wasted 2 hours on the phone and the guy kept trying to convince me this was happening because I have too many tabs opened............😀

As to VZ's support knowing about this issue; it's a tough one. The problem isn't directly in any Verizon hardware or software. It's an integration issue caused by a particular combination of Verizon and non-Verizon hardware in a particular configuration (i.e. wired Ethernet.) Verizon support is typically limited to issues entirely within their hardware and systems, so I'm not surprised by the response you got.

Like I said, we can argue all day about whose fault this is without solving anything. I'm glad you found this form and got the help you needed! Feel free to stick around and help others.

Cang_Household

@Adaminion wrote:
Thank you soooooooo much! It would be great if Verizon support learned that solution. I wasted 2 hours on the phone and the guy kept trying to convince me this was happening because I have too many tabs opened............😀

VZ engineering knows about the issue, but I guess no definitive guidance has been given to the support agents. Plus support agents are not trained in hardcore networking, so... sorry for your experience.

PghFrank

This was also the solution for an issue I was experiencing with the Outlook 365 client not sending attachments over about 200 KB.

[Deleted User]

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