Re: [DNSOP] I-D Action: draft-wessels-dns-zone-digest-06.txt

["Wessels, Duane" <[e-mail]>]

> On Mar 25, 2019, at 6:53 AM, Matthew Pounsett <[e-mail]> wrote:
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> 
> 
> On Wed, 13 Feb 2019 at 22:56, Wessels, Duane <dwessels=[e-mail]> wrote:
> The only change to this document since -05 is to note that ZONEMD has been allocated RR type code 63 by IANA following an expert review back in December.
> 
> I haven't reviewed this for a couple of revisions, so some notes here that don't apply to the new codepoint. :) . I've tried doing some searches of the discussion history to make sure I'm not raising points already addressed, but my apologies if I've missed something.
> 
> Section 2 discussion:  I was initially ambivalent about whether multiple ZONEMD records should be allowed with different digest types.  Having gone back and re-read some of the discussion, I'm persuaded that it would be beneficial to allow multiple digest types to be used on the same zone instance.  I think we'd want to have a bunch of discussion about the details in order to keep code complexity under control, though.

Thanks Matt, this seems to be the consensus, so we'll be adding some text about how to interpret multiple ZONEMDs.


> 
> Section 3.2. discussion:  Unless there's a potential benefit to non-apex ZONEMD records that I'm not seeing, I think it makes sense to forbid them.  Was there a particular thing that could be enabled by that, which prompted the suggestion?

I'm not aware of any use for non-apex ZONEMDs.  I think it comes down to the choice to either be liberal or strict in what you accept.


> 
> In 3.4.1 would it make sense to include a sentence explaining the catch-22 that would result if the RRSIG covering the ZONEMD record were included in the digest?

Added, thanks.


> 
> In section 4, I suggest replacing all of the instances of "provably [un]signed" with "provably [in]secure".

Good catch, thanks.


> Section 5 discussion: I can't remember if I commented on this bit before or not, but just in case.. I support keeping the reserved field.  It seems to me that if we have to get a new type for an incremental-friendly version of ZONEMD that we're going to have implementation fragmentation and a migration issue.  Especially if we don't allow multiple ZONEMD records, I can imagine it being difficult to have both in the zone at once, and that it could be hard to specify what should happen if an operator wants to migrate from ZONEMD v1 to ZONEMD v2 without knowing which one the consumers of their zone support

Appreciate the feedback.

DW