Re: problem statement [was Re: New Version Notification for draft-hinden-ipv4flag-00.txt]

Nick Hilliard <> Sun, 19 November 2017 22:10 UTC

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Date: Sun, 19 Nov 2017 22:10:31 +0000
From: Nick Hilliard <>
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To: Brian E Carpenter <>
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Subject: Re: problem statement [was Re: New Version Notification for draft-hinden-ipv4flag-00.txt]
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Brian E Carpenter wrote:
> The hypothesis of this draft is that there is no IPv4 support, hence
> nobody to send a DHCP(v4) reply.

It just seems operationally simpler to create a new option in dhcpv4
with simple and clear semantics than define a new flag in RA, requiring
a vendor-defined (but out-of-scope for the ID) mechanism on each host to
get each client kernel to communicate something to the dhcpv4 client to
do the same thing.  There are a lot of things to go wrong in that path,
but far fewer if you have a stub dhcpv4 server handing out "ain't no
ipv4 here" messages on an otherwise unconnected ipv4 address.

> otoh, unable to resist solutionism even in this thread, a minor update
> to RFC2131 would allow battery-powered devices to slow down the
> DHCPDISCOVER rate as much as they want to.

this would seem like an obvious and sensible optimisation.