Re: [dmarc-ietf] Ticket #42 - Expand DMARC reporting URI functionality

Alessandro Vesely <vesely@tana.it> Thu, 21 January 2021 10:06 UTC

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From: Alessandro Vesely <vesely@tana.it>
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Subject: Re: [dmarc-ietf] Ticket #42 - Expand DMARC reporting URI functionality
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On Thu 21/Jan/2021 01:05:53 +0100 Michael Thomas wrote:
> On 1/20/21 3:10 PM, Steven M Jones wrote:
>>
>> I think we should specify HTTPS URIs, and following 7489 section 12.6
>> "Secure Protocols" and current practices, HTTP should not be
>> specified/permitted.
>>
>> However I don't yet see a compelling case for the OR- syntax or a
>> separate "ruap" tag. Duplicate reports to the same destination are not
>> the base case, and the bandwidth for unintended duplicates will likely
>> be much smaller than, say, per-message DNS tree walks being discussed
>> elsewhere. Report processors annoyed by receiving duplicates can work
>> with the domain owners in question, and if that doesn't work they can
>> withdraw their report authorization record.


The point is that if you specify both mailto: and https:, a compliant report 
generator should send to both URLs.  OTOH, if you only specify https:, you are 
going to miss a lot of reports.


> See this before spending too much time. It's probably better to just junk this 
> enhancement.
> 
> https://trac.ietf.org/trac/dmarc/ticket/99


The proposed workaround implies sending base64, which is what https: is meant 
to avoid.  Your suggestion to use it as an authentication mechanism for https: 
sounds better.  You just need to add From: and DKIM-Signature: header fields, 
where the binary body is hashed as-is, that is, with no canonicalization.  It 
seems to require an easy software enhancement.


Best
Ale
--