Re: Objection to draft-ietf-6man-rfc4291bis-07.txt

Nick Hilliard <> Thu, 23 February 2017 23:38 UTC

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Date: Thu, 23 Feb 2017 23:38:18 +0000
From: Nick Hilliard <>
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To: james woodyatt <>
Subject: Re: Objection to draft-ietf-6man-rfc4291bis-07.txt
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james woodyatt wrote:
> Hmm, since RFC 6164 is a Standards Track document, it’s already
> covered as a legitimate exception under the text I already proposed,
> which seemed mostly well received, except by people who seem to think
> it’s not enough to recognize standard IETF exceptions to the /64
> subnet prefix requirement.

What's your advice to vendors then?  To disable all interface netmasks
except /64 and /127?  Or to operators?  Are you really suggesting that
"thou shalt use only prescribed netmasks on your interfaces" is a viable

This is not an idle question, btw.  Putting text into standards track
rfcs creates an expectation that the text will be built in production
code to be deployed on production networks.  What you're proposing is
straight-up Section 1 of rfc 6919.

This horse bolted 20 years ago and the shed door is long rotted.
Everyone understands that there are several situations where /64 is
mandatory, but it's terribly silly for the IETF to pretend that anyone
is going to pay the slightest attention to a requirement of this form.
They won't: vendors won't and operators won't, so we need to stop
pretending that this is a useful approach on this point.

> Some participants seem to be promising they will continue objecting
> to the promotion of RFC 4291 to full Standard until the /64 subnet
> prefix length requirement is dropped entirely. I think those
> objections should not block the advancement of this draft.

We'll need to disagree then.