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Microsoft DMARC aggregate report SMTP issues
Since 2024-02-24 06:46:45 UTC, we've stopped processing Microsoft's DMARC reports. An investigation revealed that the issue stems from Microsoft's email servers, which are transmitting SMTP commands ...
- As of 2024-03-05 16:36:46 CET, Microsoft has rolled back the changes in their SMTP transmission, and aggregate reports have begun to flow in again. The final SMTP error was recorded at 18:49:37. I haven't found an official statement from Microsoft.
I was thinking there was a way at EHLO for the client to offer extensions, but that seems not to be the case. You’re not sending anything extension side in your response to the EHLO (XATTRDIRECT, etc)?
If your server replies with that error, “501 5.5.4 Unrecognized parameter…”, does their client resend the MAIL FROM without the parameters?
Anyway I’d just have your server ignore parameters after the address in MAIL FROM.
Might be worth asking here to get info from the real experts https://www.ietf.org/mailman/listinfo/ietf-smtp
If your server replies with that error, “501 5.5.4 Unrecognized parameter…”, does their client resend the MAIL FROM without the parameters?
Anyway I’d just have your server ignore parameters after the address in MAIL FROM.
Might be worth asking here to get info from the real experts https://www.ietf.org/mailman/listinfo/ietf-smtp
To clarify, we handle millions of DMARC reports from thousands of organizations, but only Microsoft's DMARC reports (Outlook and Outlook Enterprise) have recently altered their MAIL FROM command, leading to complications. Are you implying that the rest of the internet should make alterations to their SMTP software if they want to receive DMARC reports from Microsoft? Rather than finding workarounds, wouldn't it be more effective for Microsoft to avoid sending these extra parameters in the first place?