Re: [Snac] Router using Ipv6 prefix length = 67

This is not the place to have a debate about whether longer-than-64
prefixes can be made to work. At the present time, if we advertise a /67, a
lot of hosts will simply not do SLAAC. The goal (at least in my mind) of
snac is to produce something that works. If/when the discussion in 6man
comes to some conclusion, and we start to see conforming deployments, then
we can revisit this, but at present I think suggesting that a /67 is usable
is, as a practical matter, simply not true. And that, IMHO, is what should
guide us in writing the current document.

On Wed, Jun 7, 2023 at 5:05 AM Alexandre Petrescu <
alexandre.petrescu@gmail.com> wrote:

>
>
> Le 07/06/2023 à 02:12, Ted Lemon a écrit :
> > I think it makes sense to have the definition of “usable prefix” specify
> > that the length needs to be 64 bits.
>
> I do not agree.
>
> A usable prefix is specified in the referred text as a prefix with a
> certain lifetime, not a certain length.
>
> If  one would like to specify a 'usable' prefix to be of length
> precisely 64 then there are potentially several RFCs that are impacted.
>
> That said, I generally agree with the WG consensus about the 64bit
> limits in IPv6 addressing, but these limits are rather more complex and
> they have a notion of time to it: today it is that way but we dont about
> know another day.
>
>  >> Otherwise this turns into a DoS
> > attack.
>
> I do not disagree that it can be interpreted that way.
>
> Put a router on a link sending a RA PIO plen 67 and so deny the service
> to the Non-Thread Matter Controller.  It's a DoS!
>
> The solution could be to secure that access to that link, i.e. have a
> key necessary before ability to send RAs.
>
> But I do not agree that because of that 67 there is DoS.
>
> Alex
>
> >
> > On Tue, 6 Jun 2023 at 20:03, Michael Richardson <mcr+ietf@sandelman.ca
> > <mailto:mcr%2Bietf@sandelman.ca>> wrote:
> >
> >
> >     I couldn't understand all of this thread.
> >     Is this WNP3000 receiving a plen=67 prefix from upstream and doing
> >     the wrong thing?
> >
> >     Or is this WNP3000 receiving a plen=64 prefix from upstream, and then
> >     splitting it up into 8 unuseable prefixes of len=67?
> >     Or ???
> >
> >     I agree that the SNAC Stub router needs to defend against unuseable
> >     prefixes.
> >     (It seems like it should be a call home and report situation, since
> >     nobody
> >     local will know what to do.  But that's not subject to
> standardization)
> >
> >     --
> >     Michael Richardson <mcr+IETF@sandelman.ca
> >     <mailto:mcr%2BIETF@sandelman.ca>>   . o O ( IPv6 IøT consulting )
> >                 Sandelman Software Works Inc, Ottawa and Worldwide
> >
> >
> >
> >
> >     --
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> >     Snac@ietf.org <mailto:Snac@ietf.org>
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> >     <https://www.ietf.org/mailman/listinfo/snac>
> >
> >
>
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