Feb 05 2021 06:56 AM
Feb 05 2021 06:56 AM
I believe I have spotted evidence that the answer is yes. If you look at this answers.microsoft.com thread the answer states:
Office 365 currently does not send out any DMARC reports. If it was sending out Aggregate reports, being behind a Mimecast would still generate reports for emails not filtered by Mimecast (not SPAM or Phishing). They would probably contain a lot of failures, because, for Office 365, the sending server will be Mimecast, which most likely is not added to the SPF of the sending domain. And, depending on what Mimecast is doing with the emails, the DKIM signature, if present at all, may be broken.
@The_Exchange_Team / @Greg Taylor - EXCHANGE are you able to confirm if EOP does in fact now send DMARC aggregate reports? Working with a customer whose MX records point to an on-premises mail gateway, and they're getting reports from affiliates who use DMARC in reporting mode that that their mail gateway is trying to send mail for them, unauthenticated'ly. Essentially the exact issue that is alluded to in hypothetical terms in the quoted answer excerpt above.
Thanks in advance.
Feb 05 2021 10:11 AM
Feb 05 2021 11:09 AMSolution
@Jeremy Bradshaw - Not yet Jeremy. You found the right User Voice however there is no ETA yet.
Feb 05 2021 11:35 AM
@Arindam Thokder Thank you for confirming. I also came into other findings which mooted my suspicion that it was Microsoft/EOP sending the reports. That is to say, there were many other messages sent into EXO which should/would have been in the aggregate counts of said report, so it wasn't lining up like I thought.
Apr 18 2021 10:39 AM
@Jeremy Bradshaw Now that Microsoft's Uservoice is dead, I'm curious where we should be pushing for this reporting to happen. It was an extremely popular Uservoice suggestion and never happened. The feedback options here are lackluster at best:
Apr 18 2021 04:24 PM
Apr 19 2021 10:53 AM
Aug 16 2021 01:36 PM
Aug 20 2021 02:24 AM
Aug 26 2021 06:59 AM
We have only recently started implementing DMARC and had also come across the lack of response from MS domains. How did you detect that emails were being sent from email@example.com if they were not being delivered?
The fact that only consumer domains are being used seems to correspond to this DMARC Mail (Public Preview feature) at Use DMARC to validate email, setup steps - Office 365 | Microsoft Docs
Aug 26 2021 07:23 AM
@Martin_SmulianI've noticed "Maximum allowed line length is 998 octets" errors in the mail server reject log.
Sep 16 2021 11:21 AM
Thanks all for the details and we have fixed the issue and it is rolling out.
Sep 16 2021 01:55 PM
Sep 28 2021 01:28 AM
@Arindam ThokderYou have only solved part of the problem. As of this week, the report attachment has been split into multiple lines, but unfortunately you didn't do this for the headers and body, so the entire message is still not RFC compliant.
And why do you (UTF8 BASE64) encode the subject and body, even when they do not contain special characters? I process DMARC aggregate reports from more than 3,000 organizations, and all of them (with the exception of Seznam) just use plain text, which makes processing them a lot easier.
Oct 27 2021 12:28 PM
Oct 27 2021 02:13 PM
Oct 27 2021 11:22 PM
May 03 2022 11:32 AM