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Posted by xmddmx 1 day ago

Outlook.com is rejecting email from domains without DMARC(mailroute.net)
530 points | 357 commentspage 5
shevy-java 12 hours ago|
> That rule is aimed at marketers and bulk senders, and most small businesses rightly assumed it didn't apply to them.

This would be naive. It currently means that Microsoft censors and decides what you can see in the first place. I do not recall having given Microsoft such a permission. On the other hand I don't use Microsoft for email anyway (though, unfortunately, one local university here does, which is super-annoying. Europe is unable to think strategically here).

alfiedotwtf 15 hours ago||
It’s 2026.. having been at a few email companies for years, this time I would agree with Outlook on this one
globular-toast 16 hours ago||
I've got the DMARC record on my domain, but it does seem very silly. Why couldn't the spec just make `p=None` the default?
TwoNineFive 17 hours ago||
For anyone running their own mail server, Microsoft has an authorization system to let you "authorize" your mail server IPs to talk with Microsoft's mail servers.

It's stupid, but not terribly difficult to set up and authorize.

Like most people who run their own mail, I have had repeated problems with Microsoft in particular, who treats small mail server operators like crap.

This post reminded me that I had gotten some email requesting me to "Re-attest Your Network Access". I went in, clicked a few things, and I'm good for another year or whatever.

https://substrate.office.com/ip-domain-management-snds/snds

https://www.litmus.com/blog/what-is-microsoft-snds-why-your-...

BatchJob 1 day ago||
Its not "one header" to fix. SPF and DKIM must be implemented.
bawolff 22 hours ago|
If you have no spf or dkim your emails have been getting rejected for a very long time.

(dmarc only requires one of spf or dkim, not both, but it is a good idea to use both)

apparent 18 hours ago|||
Not IME. I just added all 3, after not having any noticeable email issues for years.
jeroenhd 10 hours ago|||
Unfortunately, SPF and DKIM become optional once you send enough email for a mail server to trust you. You could've never bothered to update your email to the futuristic year of 2015 and still made your way into every inbox without ever knowing you forgot something.
almost 1 day ago||
Yeah thanks Microsoft. Really appreciate having to mitigate this for hundreds of customers on a weekend. Nice one!
esikich 1 day ago||
You should have done this for your customers years ago, yikes.
urbandw311er 1 day ago|||
I suspect that he/she means they runs a mail server and it was up to his customers to comply, but now they’ve had to deal with the fallout from their customers not complying.
esikich 1 day ago||
Cool, charge them for it. That's what IT support is.
almost 1 day ago|||
The customers have to do it themselves since they control their domains. I recommend doing everything correctly but also understand that this stuff is pretty hard for people just trying to run a small business. But if it makes you happy to feel smug you can carry on assuming.
esikich 1 day ago||
My assumption is that they were in control of the domains. If not, it isn't their problem and if anything it's billable hours, aka their job.
jrhite 18 hours ago||
[flagged]
davisr 1 day ago||
I noticed this when it happened, but I do have a valid DMARC entry (albeit p=quarantine).

https://mastodon.social/@davisr/117570496362439342

Pxtl 21 hours ago||
Email is dead. Unfortunately any replacement for it would be owned by Meta or MS or whatever.
cowlevel 18 hours ago|
The assumption of a single shared medium is dead.

When you talk about a single entity to single entity connection it can be any protocol. Email, Matrix, WhatsApp, SMS... Discord... Instagram. All of them work especially if you whitelist the other party.

What doesn't work any more is assuming that everyone is using the same thing. Back when email was invented it was the only computer-based communication protocol - I don't remember whether it came before or after USENET - I'm assuming before. If you wanted to send a message to someone you sent it to their email address. Now things aren't so clear.

daneel_w 1 day ago||
It's possibly yet another issue relating to the long streak of problems seen the recent months by primarily self-hosters trying to reach people and businesses behind Outlook servers. The past few weeks a lot of my e-mails to friends and family using Hotmail have gone missing. All envelopes were OKd by Outlook servers, nothing bounced, e-mails just gone. My setup is clean, my network is clean.
SoftTalker 1 day ago||
I'm fine with providers imposing some default level of spam protection but as a user I'd like the option to disable it, even better if I can disable it per domain or sender. The old technique of adding the sender to your contacts doesn't work reliably anymore.
daneel_w 1 day ago||
"The old technique of adding the sender to your contacts doesn't work reliably anymore."

An Outlook user first reaching out to you, and you replying and including the unique message-ID of their original envelope in your headers, doesn't affect anything either. Absurd. The whole situation is complete dog shit.

pamcake 1 day ago||
"First time?"

It's not months it's years.

daneel_w 1 day ago||
Anecdotal. I've self-hosted for many years but didn't run into these issues with O365 until this year. But not surprised to hear it.
cowlevel 18 hours ago||
They used to just drop all messages from domains not on their whitelist and to get whitelisted you needed to have a Microsoft account and open a support ticket.
dwm 1 day ago|
They're not rejecting them quietly. They're sending 5xx permanent delivery failures.
lelandfe 1 day ago|
The title may mean it in the sense of being unannounced
mailroute 8 hours ago|||
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TwoNineFive 1 day ago|||
"Quietly" in the title is an AI slopspam pattern. It's an over-used teenager hyperbolic crutch word on par with "literally", "actually", "honestly" and similar.

Sometimes it's use is appropriate, but not in this case. Microsoft announced this change loudly, multiple times, starting more than a year ago. I seem to recall one of those announcements being discussed here on HN. Even the article links to it's own previous announcements, so "quietly" here is stupid rage bait to justify a blogspam advert.

dwm 16 hours ago|||
The word "quietly" has now been dropped from the link title, but still appears on the original.
nottorp 13 hours ago||
Real men do not review their articles, they post them on HN and have the whole world review them :)
mailroute 8 hours ago|||
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