Re: Confirmation to advance: draft-ietf-6man-ipv6only-flag-05

[David Farmer <[e-mail]>]

On Mon, May 27, 2019 at 5:20 PM Sander Steffann <[e-mail]> wrote:

> Hi Nick,
>
> > Op 27 mei 2019, om 23:08 heeft Nick Hilliard <[e-mail]> het
> volgende geschreven:
> >
> > David Farmer wrote on 27/05/2019 20:23:
> >> But it's not DHCPv4 we're actually talking about but the robustness
> IPv4 to a failure of DHCPv4.  So let's be clear, Philip is proposing
> reducing the robustness of IPv4 in the presence of IPv6, at least the
> robustness of on-link communications with IPv4. Whereas using the flag only
> reduces the robustness of IPv4 in the presence of the IPv6-Only Flag. While
> I'm fine with either option, many people objected to tying IPv4 and IPv6
> together, but which of these two options does more violence to IPv4?
> >
> > personally, I don't think either of these options is compelling - and
> separately, would tend to agree with the idea that causing different
> protocols to share fate is something that should be avoided, unless there
> are overwhelmingly good reasons to do so.  So the question of which "does
> more violence to ipv4" seems more like a question along the lines of "each
> option has its problems, but which is the least bad?", to which I'm
> inclined to answer: "well, neither is necessary, nor advisable, so maybe
> neither option would be best".
>
> I agree.
>
> I think for migrating to IPv6 the RFC2563 option is perfectly acceptable:
> as long as you have IPv4 clients on your network, tell them in their own
> "language" that there is no IPv4 service on this link. When those clients
> disappear over time stop providing DHCPv4 completely and happily enjoy a
> clean IPv6 network. There won't even be a legacy ipv6only flag ;)
>
> Cheers,
> Sander
>
> PS: yes, I know there are some with a purist "I don't want ANY non-IPv6
> packet on my network" view, but seriously, let's focus on real-life
> problems…
>

Then stop telling people to filter Ethertype 0x0800 because you can't use
RFC2563 in the presence of such filters. Further, there really aren't IPv4
clients and separate IPv6 clients anymore, just about everything that
matters is dual-stack. So you are really saying, tell dual-stack clients to
not use IPv4 using IPv4. So who is the purist? You're saying you can't
block IPv4 because you have to use IPv4 to tell dual-stack clients they
shouldn't use IPv4, now that's a catch 22.

Again this is a real problem is some at least a few situations, and they
are fairly common situations, just not in the home broadband world at least
today.





-- 
===============================================
David Farmer               Email:[e-mail]
Networking & Telecommunication Services
Office of Information Technology
University of Minnesota
2218 University Ave SE        Phone: [phone]
Minneapolis, MN 55414-3029   Cell: 612-812-9952
===============================================