On May 29, 2013, at 12:36 PM, John C Klensin <john-ietf@xxxxxxx> wrote: > If I had been able to figure > out what else to say that would be stronger, constructive, and > not stray into Applicability Statement territory, I would have, > so I'm out of ideas and it is possible that Joe is too. Even if you don't have an applicability statement, I don't think it's inappropriate to talk about the context in which the documented protocol is intended to be useful, nor to talk about contexts in which it wouldn't be appropriate. The document currently is far too restrained in this regard, IMHO. I would add some text to the introduction, like this: The DNS Resource Records described in this document have significant privacy implications (see section 8). They were developed with the intention to use them in [scenario a] or [scenario b] and are likely not to be appropriate in other scenarios. In particular, they are unlikely to be appropriate for use in DNS zones hosted on globally-reachable servers that will answer any query without any access control mechanism. I realize this looks a lot like an applicability statement, but the problem with putting an applicability statement in an Informational document is that informational documents are never applicable in the sense of being the standard the IETF recommends to use in a specific case. As long as you stay away from _recommending_ the use of this specification, I think it's okay to say where its use was envisioned. Although of course if it was envisioned to be used on the public internet, that wouldn't help.