Re: [dmarc-ietf] Discussion - ARC/Extensible Reporting (Ticket #56)

Alessandro Vesely <vesely@tana.it> Thu, 03 December 2020 19:44 UTC

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From: Alessandro Vesely <vesely@tana.it>
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Subject: Re: [dmarc-ietf] Discussion - ARC/Extensible Reporting (Ticket #56)
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On Thu 03/Dec/2020 19:54:51 +0100 Brotman, Alex wrote:
> 
>> -----Original Message-----
>> From: dmarc <dmarc-bounces@ietf.org> On Behalf Of Alessandro Vesely
>> Sent: Thursday, December 3, 2020 6:24 AM
>> To: dmarc@ietf.org
>> Subject: Re: [dmarc-ietf] Discussion - ARC/Extensible Reporting (Ticket #56)
>>
>> On Wed 02/Dec/2020 20:46:54 +0100 Brotman, Alex wrote:
>>>
>>> While this ticket/enhancement specifically mentions ARC, I could
>>> perhaps see the usefulness in other places.  It seems like it would be
>>> more beneficial to create a method by which other documents could
>>> provide XML- based "extensions" to the report.  This would allow
>>> mechanisms relying on DMARC to independently define their reporting
>>> schema to be included in DMARC aggregate reports.  Alternately, we could
>>> focus specifically on ARC, and work to include that in the base XML.
>>> This means that any later reporting requirements could again require
>>> changes to the core drafts.>>>
>>
>>
>> Another possibility is for ARC to define its own report format.  Hijacking
>> rua= targets to send a different kind of report should be allowed.
>> Otherwise, we could define a new tag, e.g. rue= (e for Extension).>>
>> In either case, as we're introduce variations in aggregate report content,
>> we have to devise a method for determining what version/kind of report is 
>> attached to a given message.>>
> 
> We could add an element called "<extensions>", and we allow ARC or whatever
> it may be to exist under that element.  The Aggregate Reporting document
> needs to specify that any extensions are expected to be proper XML, and if
> there are no extensions, an empty element is sufficient.  We could create a
> bit more structure as a requirement if we wanted:> 
> <extensions>
>    <extension name="arc" standard="ARC_DMARC_REPORTING_EXTENSION_DEFINITION">
>      ... (as defined in referenced standard)
>    </extension>
> </extensions>
> 
> If a report parser doesn't know what ARC is (or any of the extensions), it could skip the processing.  I do understand this means that <extensions> element may break existing parsers, even when empty, though, I expect many of the things we're proposing may fracture the expected XML.


We can do a better job at producing aggregate reports with an automatically verifiable content.  For example, prepending stuff like this:

<?xml version="1.0" encoding="UTF-8"?>
<dmarc:feedback xmlns:xs="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:dmarc="http://dmarc.org/dmarc-xml/0.1"
	xs:schemaLocation="http://dmarc.org/dmarc-xml/0.1 rua.xsd">
	<report_metadata>
        ...

(Perhaps something better than "http://dmarc.org/dmarc-xml/0.1" for the version)

But then, would the <extensions> imply dmarc-xml grammar should be upgraded every time ARC (or whatever) is upgraded?

Separate reports sounds simpler.


Best
Ale
--