WIndows Updates Fail Via IPv6

Mark Andrews marka at
Mon Nov 12 22:34:07 UTC 2018

Which just shows content providers and tunnel end point problems.

* load balancers that don’t properly handle ICMP{v6}
* stupid firewalls that block PTB
* tunnel end points that don’t generate PTB for EVERY oversize packet
  (you wouldn’t drop TCP ACKS and PTBs are just as important)

PMTD requires PTBs to be generated.

Report the problems so they can get fixed.


> On 13 Nov 2018, at 6:08 am, John Von Essen <john at> wrote:
> I recently go a Linksys home wifi router, by default it enables ipv6 on the LAN. If there is no native IPv6 on the WAN side (which is my case since FiOS doesnt do v6 yet) the Linksys defaults to a v6 tunnel.
> For the first few weeks of using the router, I had no idea alot of my traffic was going out via the v6 tunnel.
> Then I started getting random reachability and availability issues. Google would not load, but Bing and Yahoo would, and so on. I thought it was a FiOS issue, but after digging, I discovered the v6 tunnel, disabled it and all my issues went away. 
> I dont know what Linksys uses for the v6 tunnel because its buried in the firmware, but any tunnel service is vulnerable to a variety of issues that could effect access. Its odd that it always effects Windows update all the time, but who knows.
> -John
> On 11/12/18 1:18 PM, Mark Tinka wrote:
>> On 11/Nov/18 18:51, Lavanauts wrote:
>>> I’m on native IPv6 via Spectrum and have no problems with Windows Updates.  Could this be a tunneling issue?
>> I do run 6-in-4 from my backbone to my house as my FTTH provider does not do IPv6.
>> I can't imagine this to specifically be the issue, as all other IPv6 traffic is fine, but at this point, I'm open to suggestion.
>> Mark.

Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: marka at

More information about the NANOG mailing list