Subject: [DNSOP] Adam Roach's No Objection on draft-ietf-dnsop-isp-ip6rdns-06: (with COMMENT)

From: Adam Roach <[email-masked]>
Date: Tue, 25 Sep 2018 16:14:38 -0700

Adam Roach has entered the following ballot position for
draft-ietf-dnsop-isp-ip6rdns-06: No Objection

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COMMENT:
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Thanks for the thought and work that went into this well-written document. I
have only two relatively minor comments.

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§2.1:

>  For best user experience, then, it is important to
>  return a response, rather than have a lame delegation.

In light of [1] (and its ensuing thread) and [2], the authors may wish to
consider a different term than "lame" for this description.

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[1] https://mailarchive.ietf.org/arch/msg/ietf/W6wSh3TDfetVY6eeDAu8FNcCKeA
[2] https://en.wikipedia.org/wiki/List_of_disability-related_terms_with_negative_connotations

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§2.5:

If I read things correctly, A naïve implementation of what is described in
this section would result in the nameserver using some amount of state for
each IPv6 PTR record that was queried, for the duration of the TTL. Given the
extraordinary expanse of IPv6 space that such a server is likely delegated, it
seems that there's an attack in here whereby an attacker asks for an arbitrary
number of PTR records within a single server's range, each resulting in
additional memory consumption for whatever time period the TTL represents.

There probably should be some text in here warning implementations to guard
against such attacks either by limiting such storage, or by generating such
names in a deterministic way such that they don't require cacheing or
pre-populating AAAA records (instead generating them on the fly)