Re: I-D Action: draft-ietf-6man-ipv6only-flag-03.txt

[Lee Howard <[e-mail]>]

I've been meaning to say the same thing. I don't think there's astronger 
advocate for IPv6-only than I am, but I have some misgivings on this 
document that I haven't quite been able to articulate.

I haven't been following the discussion closely, but have we heard from 
any OS developers about what they plan to do if they see the flag?

I don't need to see code deployed in the wild, but I sure would like to 
have some hint from implementors what will happen in the wild. Different 
implementations might well intepret the flag differently, which might 
result in some surprising behaviors on the wire(less).

For instance:
Devices come up with at least IPv4 enabled and start sending some kind 
of local multicast, maybe doing service discovery over IPv4. Then a 
router sends the IPv6-only flag. If some hosts recognize it and others 
don't, they may try a service that has previously been advertised over 
IPv4.
Does Happy Eyeballs solve this? I don't know whether printer services 
implement that, though I know that on my dual-stack network I can't 
print if I lose IPv6.

So I'd like to see how OSs will detect and recover.

Lee

On 10/19/2018 08:35 AM, Job Snijders wrote:
> I think it would be good to have some running code before advancing 
> this to IESG review and RFC publication. I don’t mean someone being 
> able to send the flag in a RA, but an operating system reacting to 
> receiving a RA with the flag set.
>
> Operating system implementers will be able to provide valuable 
> feedback to the working group on how to mitigate risk for some of the 
> suspected attack vectors - and it’ll be educational to see how this 
> works in practice. I think running code will improve this specification.
>
> Kind regards,
>
> Job
>
>
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