Mike Wertheim writes:
I'm running an email list on mailman3.
My users are getting inundated by messages saying that their subscriptions have been disabled due to their bounce score exceeding the mailing list's bounce_score_threshold.
But there is nothing wrong with these users' email accounts. They are all perfectly fine. Apparently the issue is somehow related to spam.
You don't say, but I assume you've checked and the users are actually disabled?
Are these users on Office365 or related MSFT product? My employer switched from Sendmail inhouse to Microsoft-hosted Exchange/Outlook, and ever since I'm getting scores of these:
From: Microsoft Outlook <MicrosoftExchange@O365tsukuba.onmicrosoft.com> To: <turnbull.stephen.fw@u.tsukuba.ac.jp> Subject: Undeliverable: Clinical Studies enrolling now - Get Paid! Date: Sat, 17 Jun 2023 01:50:44 +0000 Message-ID: <REDACTED>
Your message to turnbull.stephen.fw@u.tsukuba.ac.jp couldn't be delivered. When Office 365 tried to send your message, the receiving email server outside Office 365 reported an error. turnbull.stephen.fw Office 365 turnbull.stephen.fw Sender Action Required Policy violation or system error
These spam messages are all allegedly from *me* to *me*! It turns out that they're being rejected at *another* O365 site. The original From is something else (not sure if it's relevant), the original "to" is a virtual mailbox of mine that the site forwards to me, and by the time they get forwarded to me O365 manages to completely confuse itself.
They all go through my local Postfix and just end up in my spam folder, but clearly O365 is really broken when it comes to filtering and delivery status notification. Because I have control of my local mail system and just use O365 as the border MX, I haven't bothered to see if I can automate beyond filtering into the same cessbucket as the other spam, but maybe there's a hint for filtering out these bogus bounces.
@Mark I've been seeing an unusual number of disabled subscriptions on python.org and mailman3.org lists recently. Maybe we should look into this. If you haven't seen this O365 breakage, I can send you some samples.
Steve
-- Friends don't let friends use Microsoft Exchange.