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

[David Farmer <[e-mail]>]

On Sat, May 11, 2019 at 3:39 PM Fred Baker <[e-mail]> wrote:

> And for the record, Job, Nick, and Sander are not the only ones that are
> not members of the putative consensus. I have stated (would have to look it
> up to give you the link to the email and the date) that IMHO the benefits
> are minor and there is a security loophole. My issues remain unaddressed.
> So I'm part of the anti-consensus. And I'm pretty sure I'm not alone.
>

Fred,

Please correct me if I'm wrong, but I believe your objection is that it
would be more efficient to simply perform exponential backoff on the IPv4
DHCPDISCOVERS. Do I have that right? If not please help me better
understand your objection.

In my opinion, you are correct if that were the only or even the primary
source of futile IPv4 traffic. In effect, RFC 3927 configures a Link-Local
IPv4 scoped address if a DHCPOFFER is not received, and then this
Link-Local address is used to perform futile IPv4 service discovery. From
my perspective, this is the primary problem, not futile IPv4 DHCPDISCOVERS.
As you say exponential backoff of the DHCPDISCOVERS would easily control
that issue. However, something also needs to signal the dual-stack host to
not perform IPv4 service discovery because the dual-stack host is on an
IPv6-Only network, I believe this flag serves this purpose well.

Further, as of late I've been trying to listen very closely to the
objections. In listening to the objections, I came up with the concept that
the lack of IPv4 DHCPOFFERS should be considered the primary signal and
this flag is a secondary signal mainly intended to disable IPv4 service
discovery.

Thanks

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