nanog mailing list archives

Re: WIndows Updates Fail Via IPv6


From: Bjørn Mork <bjorn () mork no>
Date: Tue, 13 Nov 2018 12:40:37 +0100

John Von Essen <john () essenz com> writes:

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.

Could this be a 6RD tunnel requested by your ISP using DHCP with
OPTION_6RD? Ref RFC5969

Setting up any tunnel to some pre-configured endpoint by default does
not sound like a good idea....  But DHCP on the WAN side is "trusted",
so configuring a DHCP requested tunnel by default is reasonable.

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.

It would be great to have more details about this default tunnel setup.
Can't you sniff the traffic?

Anyway:  Thanks for yet another argument for native dual-stack.
Avoiding such unwanted tunnels is really simple:

If you're an ISP:
  Offer native dual-stack to your Internet access customers.

If you're an Internet access customer:
  Request native dual-stack from your ISP

Problem solved.


Bjørn


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