Outlook.com Is Quietly Rejecting Email from Domains Without DMARC

Re:Outlook.com Is Quietly Rejecting Email from Domains Witho... by stevekemp on Sunday November 08, 2026 @03:00PM (#50416580)

It seems like 90% of the spam I receive (on my google account) is sent from google addresses, so it will have valid SPF/DKIM/DMARC setup.

That said checking for these things is a good idea, the only problem I see is dropping the mail on the floor, rather than rejecting it at SMTP time - at least that lets the self-hosting users who haven't got things configured know their email is being rejected, and to pick up the phone instead.

There's nothing worse than sending an email, it being accepted, and then later discarded with no clue to either sender or recipient.

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Re:Outlook.com Is Quietly Rejecting Email from Domains Witho... by shye on Sunday November 08, 2026 @03:15PM (#50416687)

Selection bias: you don’t see the spam that get rejected at HELO.

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Re:Outlook.com Is Quietly Rejecting Email from Domains Witho... by cowlevel on Monday November 09, 2026 @12:40AM (#50421490)

My server doesn't reject anyone, but does greylisting. That's a default setting in Postfix. It means the first time an IP address connects it gets a temporary error. If it retries later the message is accepted. That's the only anti-spam measure I have.

Maybe 1 in 5 emails I get is spam, and because I use a different address with every sender I know who sold "my" address to a spam list.

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