Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds

Fernando Gont <> Fri, 01 November 2019 03:07 UTC

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To: Owen DeLong <>
Cc: Ted Lemon <>, v6ops list <>
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From: Fernando Gont <>
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Date: Fri, 1 Nov 2019 00:02:30 -0300
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Subject: Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds
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On 31/10/19 16:38, Owen DeLong wrote:
>> On Oct 31, 2019, at 12:21 PM, Fernando Gont <> wrote:
>> Hello, Ted,
>> On 27/10/19 09:02, Ted Lemon wrote:
>>> Indeed, this would also not actually solve the problem.   At present,
>>> the ISPs are doing something that is out of spec and causes problems.
>>> If we “fix” this by accommodating what they do, does that help, or
>>> does it just encourage them to continue doing it?
>> Did happy eyeballs encourage broken IPv6 connectivity, or did it
>> actually help IPv6 deployment?
> Considering these mutually exclusive is a false dichotomy.
> It did both.

It's hard for me to believe that folks were breaking stuff on purpose.

In any case, I would assume and expect that helping IPv6 deployment was
more of a priority at the time. IN fact, we wouldn't be talking about
"google seeing 25% of IPv6" if there wasn't a way to circumvent
brokenness, I'd assume.

>>> When another RA arrives, see if it was signed with the same key.   If
>>> so, it came from the same router, and can be trusted to update
>>> whatever information that router sent, including flash-deprecating a
>>> prefix.   If not, ignore it.
>> In the non-SEND trust model, you do trust the local router. Why did you
>> trust the local router to configure your network, but not for
>> deprecating the prefix?
> Trusting the local router to configure the network to add a previously non-operational host to the network has a somewhat different set of consequence for failure than trusting whatever on-link host wishes to tell you to effectively shut down your currently operating network connection.

We'll that's the SLAAC model.

> Especially when you consider that such an announcement can be sent to the all nodes on link multicast address, effectively dropping them all at once.
> I agree it’s not a huge difference, but, it is a difference and certainly the scope of the resulting problem can be much larger than the case of individual host configuration.

Hosts trust a lot of other crap. e.g., feel free to advertising a Cur
Hop Limit of 1. Is that any different?

Fernando Gont
SI6 Networks
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