I actually totally agree with this. There's too much risk involved with scams disguised as legitimate services because the developers of said service couldn't be bothered to add 1 or 2 dns records.
Although there seems that there hasn't been any communication which is the bad thing here. However, nobody looks at those and sending detailed emails back seems like a good enough solution.
I don't know what "v=DMARC1; p=none;" is proving to anyone when DKIM and SPF are already aligned but sure whatever. Just wish they'd given some warning!
Agreed. There's no additional verity provided by adding a DNS record with a static line of text. Reminds me of airport security theater: meaningless hoops for citizens to jump thru under the guise of stopping bad actors.
This is interesting. At some point, I think it'll be desirable to give increasing positive weight to emails with the DPF/DKIM/DMARC trifecta configured, since those are least likely to be problem emails (spam or phishing), but I wonder what the best avenue is to actually make that the default. It's almost certainly not this kind of unannounced cutoff.
Email is, I think, among the most distributed popular online services, and there's a ton of stuff that's legacy, self-managed, or otherwise janky. Supporting SPF, DKIM, and DMARC does put a burden on independent operators, but is it an undue or unreasonable one in the current landscape? Or is it just the new cost of doing business?
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.
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.
> I wonder what the best avenue is to actually make that the default. It's almost certainly not this kind of unannounced cutoff.
En contraire, I think not delivering mail is the fastest way to adoption. People will use an old system for as long as it works. It now does not anymore.
I don't know. I think this disenfranchises a lot of independent operators, and the blow of that could at least be softened by making a highly-visible public announcement about it a few months ahead of time.
Maybe you're right that just enforcing it is the way, but I don't agree with doing that with no heads up.
Most spam I get is from Google, Microsoft and Amazon. We should pressure those to start dealing with the problem. Right now they are conveniently ignoring it.
You can literally just Google a 3 step guide for any provider. What are you even arguing? That security for infra shouldn't be a thing? Should grandma be able to run a mail server? What's your point?
Requiring HTTPS was very unreasonable. You have so many more moving parts that can go wrong, and a business relationship with a CA (even if it's Let's Encrypt). We only tolerate this because the alternative is worse.
None of them are a good 'Is this spam?' heuristic, though. All they do is ensure the sending domain isn't forged, but most spam, even phishing emails, doesn't really rely on that. Spammers are much more motivated than average to jump through the hoops necessary to set it up, as well. Any anti-spam signal needs to be much more expensive for spammers than regular senders.
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.
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-mail to friends and family using Hotmail have gone missing. Submits were OKd by Outlook servers, nothing bounced, e-mails just gone. My setup is clean, my network is clean.
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.
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.
I thought they've been doing this for years, along with gmail/etc. I basically just added setting up the correct DNS records as part of business when sending emails externally.
I’ve been anticipating something like this for a while; the number of folks who don’t have their email-related DNS settings in order is remarkably high.
I have MCP servers for the creation of domains, DNS records with DNSSEC, and email accounts with SPF, DKIM and DMARC. I'm sure if someone wants to be a professional spammer today, DMARC is not a differentiator.
It's an interesting argument. The fact this article exists is somewhat proof that it is a differentiator. The flipside, however, is that spammers very specifically require their emails to get to add many mailboxes as possible, so their motivation is greater to make their emails service compatible.
Company sys admins have likely got all sorts of other issues to worry about, and the occasional report of an email not getting through is likely low on their to-investigate list.
Having said that, I self host a mail server, and have all those things setup correctly, and my workplace uses Outlook, and I've not had issues with delivery, so it's not a particularly difficult bar to jump.
What? How does it prove it's a differentiator for someone who wants to be a spammer, which is what the comment you replied to made a claim about? As far as I can tell, it's evidence (not proof) that Microsoft thinks that they will reduce spam by requiring it, which in turn is circumstantial evidence (definitely not proof) that spammers might have to spend some amount of effort to start using DMARC. I don't understand how you can conclude that it would be onerous for them to do so indefinitely; it seems equally plausible that they might have just not bothered to do it before now but will be able to start doing it without much cost.
"Lazy people"? I only heard about this because a customer complained. Am I supposed to go around the Internet, checking what each mail server will allow or deny?
To be fair, DMARC has been required for a very long time. IIRC Google warned about 2 years ago circa that non-compliant emails would land to spam or be null-routed. And the DMARC noise started even before that.
Gmail only requires DMARC for senders that send >5000 emails per day. Below that it's not required. That rule only appeared in 2024 so I wouldn't say it's been required for a very long time. Perhaps you're thinking of DKIM, which is different.
This seems overly dismissive especially for individuals who send emails from custom domains at low volumes. DMARC has previously been seen to only be really needed for high-volume senders. The mail testing service linked still gives 10/10 for emails received without DMARC (but with SPF and DKIK). My email is setup via Fastmail and I followed all the recommendations they provided (which didn’t include DMARC)
I just tried this out now with an email from my personal domain that I have configured to send via my gmail account. I got a 10/10, but DMARC does not seem to be required for this. It shows a yellow checkbox for me on this, the same as it shows for me not having an unsubscribe button, which hardly gives the impression of it being necessary, given that I would not expect an unsubscribe button to make sense for most people manually sending emails to their customers from corporate email accounts.
Delivery to Microsoft's products has been patchy for several years. I am not remotely an email deliverability expert but I have made different SMTP service choices based on how companies approach shared-IP sending plans.
Some can affordably deliver to Microsoft because they aggressively police what they are actually sending on their customers' behalf; others don't get involved and you end up having to spend a fortune on a dedicated IP.
The DMARC thing is just another part of this; one of my clients discovered this silent failure themselves a few weeks back and addressed this.
If running a mail server is central to your business, you should keep up with best practices. If not, 2 days of non-delivery aren't important, just resend.
You don't have to, this is the key reason to have a DMARC monitoring service. It will tell you when there's a deliverability issue with some particular receiver.
DMARC applies not on your mail server, inbound or outbound, but on the server that is receiving your mail (which may in fact be your mail server).
That server will look at how the mail authenticates and decide if it should allow the mail to proceed, it (for the most part) will then tell you whether or not it allowed the mail. This is how you will know you might have a deliverability problem before your customers do.
> You don't have to, this is the key reason to have a DMARC monitoring service. It will tell you when there's a deliverability issue with some particular receiver.
It's been a while, but monitoring DMARC seemed pointless once you got things started. If my outbound mail fails to validate, I've asked the receivers to bounce it, and I should be able to see that on my own system.
Otherwise, I'm just getting reports about spoofed spam or people who need to adjust their mail forwarding, but I can't do anything about either.
right, if you're at a reject status DMARC monitoring is (and should be) boring.
But it provides a safe guard against accidentally broken mail flows as your email stack evolves over time which is where it pays dividends.
I would love to say that it would have alerted you ahead of time to this particular event, but given that it's the fix here you would never have seen it.
DMARC is a DNS record that says "send emails about spoofed messages here", or optionally "I don't need you to tell me that scammers exist on the internet".
It doesn't prevent spoofing, it doesn't say which IPs are authorized to send on behalf of a domain, it doesn't sign messages. Spoofed messages are still sendable.
Can you explain the benefit of only accepting email if Microsoft knows that you may or may not accept emails about scammers unsuccessfully spoofing your email domain? (Note, there's nothing you can do if they do tell you.)
Don't confuse DMARC with DKIM or SPF; DMARC doesn't actually do anything for email security.
That is not true. Reports are just one of the features of DMARC. The policy which allows you to instruct senders what to do with unauthenticated emails is the much more relevant part an when the receiver follows it, it very much does prevent spoofing.
And what should a provider do if the dmarc policy says that none of the dkim or dmarc records should matter? What was the point of spf saying what servers could send, or dkim specifying signing keys?
"Oh, please, don't ignore the other two ways I told you to ignore unauthorized messages" shouldn't need a knob.
You get an email without a DKIM signature from me.
Is that because I do not use DKIM and do not sign my emails or because the message is forged and not from me at all?
You cannot tell. There is a single SPF record that you can look up to see if SPF is configured. It's just a TXT record on the domain. But there is no standard DKIM record. A DKIM signed email tells you what key identifier it used and you have to use that to look up the DKIM key at <key identifier>._domainkey.<sender domain>. When the email has no DKIM signature you cannot tell if that's because the sender domain does not use DKIM or if it does have a DKIM key record but it was not used, potentially because the email is forged.
You'll have a bad time if you just drop all emails without DKIM. There are many large senders that do not care about well established email standards and you will drop important emails.
I kind of have to agree. DMARC is not new. It's useful and helps make email safer. It's not even hard to set up. There's just no reason for any legitimate mail provider not to use it. Same for people who are technical enough to run their own mail servers.
I was hit by this twenty minutes ago. I don't disagree with the policy, but I wish my provider had warned me so I could add the headers. I already had DKIM and SPF, but not DMARC.
That's an old announcement about a different change. As far as I can tell this one is completely out of the blue. I'm shocked by the number of people in this thread advocating for spontaneous changes without any warning.
This has been going on for much longer than stated here - we had domain mismatch issues with outlook going back years and our policy was p=none. They’re very sensitive and mailing lists with forwarding are heavily impacted.
I have a bunch of email accounts which have SPF and DKIM, but are missing the DMARC line - I've had no deliverability problems at all, until this weekend, and now only with Outlook. Emails to Gmail accounts go through just fine.
The combination of:
√ Valid SPF
√ Valid DKIM signature
X Missing DMARC policy
Is clearly ambiguous. Since a DMARC of "p=none" (in the context of valid SPF and DKIM) really adds no information, so interpreting "missing DMARC" as "p=none" seems reasonable. Sounds like Microsoft was taking that approach until this weekend.
Under RFC 7489 [1], a domain with no DMARC record simply has no DMARC policy, the receiver is able to enforce whatever policy it likes.
Most receivers have chosen to treat this as p=none for the last decade (Microsoft included). This is changing to now so that mail with no record is simply refused. Nothing in the standard prohibits this.
a DMARC of p=none might be seen as ambiguous - SPF and DKIM have their own jobs and they work. However, the point of DMARC is not a new way of enforcing mail authentication. Instead it is a way of making certain that the mail is internally consistent and furthermore provides two additional things.
1. it indicates if the domain owner has thoroughly gotten their mail to authenticate (in which case they adopt a p=reject), and
2. it provides a feedback mechanism that allows the domain owner to know if they are seeing authentication and deliverability problems in such a way that they can fix those broken mail flows.
Googling around this started at least a year ago, but I worked at an MSP 3 years ago when it was first announced and we started getting customers into compliance. This wasn't something out of the blue.
This was my second hackernews submit [0]! So, not even https in 2014 :)
When I ran that server, outlook.com was also the only one that would blackhole my email for no known reason. Support was unhelpful and also could not point to any reason. I've since given up, but for a short time it was glorious, email to family would not leave the lan and we could send attachments of arbitrary size.
You adopted it the moment it was announced? Really?
Is there a risk some people on this thread are mixing up DKIM and DMARC?
DKIM = proving that an email was sent from a specific domain using cryptography. Good for spam fighting and deliverability.
DMARC = telling receivers how to handle mail that fails authentication.
DMARC is primarily useful for large, complex organizations where email admins may not be aware of everyone inside the org who is sending mail that advertises the domain in the From header, or organizations that might be targeted by impersonation attacks (e.g. phishing). Being able to tell recipients "yes we absolutely have our act together so feel free to reject or spamfolder unauthenticated email" is great for killing phishing campaigns, and being able to request reports is great for finding that one sales org that signed up for a guerrilla marketing SaaS that's impersonating them.
But for small personal domains the value isn't that high.
I added DMARC and DKIM together, around the same time as some particular life events 10 years ago. Just now, I cross-checked the information against the commits in my Git repos.
Back then, I didn’t use Terraform or anything like that, but I had text files with logs that described the DNS setup in detail so I could fix things. By grepping through the logs, I’m able to put a definitive bound on when I added DMARC—it was no later than June 2016, over 10 years ago.
At the time I thought, “Obviously, we should all be setting this up, because recipients will start rejecting mail from insecure domains, if they don’t already.” This was also back when I self-hosted email. I eventually stopped doing that because I thought it was too time-consuming.
>DMARC is primarily useful for large, complex organizations
>But for small personal domains the value isn't that high.
I don't understand the resistance. It benefits the entire mail ecosystem, not just mass senders.
SPF used to be niche thing, then everyone realised it's a good idea and it became more-or-less mandatory. Same with DKIM. Now it has happened to DMARC as well.
I have the opposite problem. I have a 3-letter email address, so for ease of giving out the email address, I use it, while having it forwarded to my Gmail. Somewhere around 2019, emails from legitimate services, especially password reset/OTP codes, stopped landing in my inbox or even junk because my address is so high up the chain of spammers. Nebula was the first to confirm this for me and work out of band to re-enable access to my account - their emails to me were bouncing. But ever since that happened, I’ve slowly moved back to giving my Gmail.
It sounds like Gmail is seeing 3000 emails a day coming from foo@bar.com, some of which are different kinds of spam, and reasonably concludes they are a spammer.
"ARC was devised to solve this problem by giving intermediate servers a way to sign the original message's validation results. Even if the SPF and DKIM validation fail, the receiving service can choose to validate the ARC chain. If it indicates that the original message passed the SPF and DKIM checks, and the only modifications were made by intermediaries trusted by the receiving service, the receiving service may choose to accept the email."
Outlook.com is also rejecting mail based on blocklists that are not public and you essentialy cannot get yourself out. My VPS provider is pretty much entirely blocked and their regular blocklist process says we are golden so nothing to unblock.
Outlook.com and similar are an anathema to email. This is why they tell you not to run a mail server .
On the other hand rejecting domains without dmarc is fine. Just not happy it is silent.
At the most you need to use an external service for delivery (usually because you have problems with MS) but you can still run your own server with no difficulties once you do that.
That said, DMARC is required by a lot of people now, so I do not think this particular issue is a problem.
I have been self hosting my my personal email (and for family). Few problems so far other than delivery to MS and I have recently moved a domain I use for work email over.
Oddly enough the MS problems come from hotmail, but not other services. If that is a problem, then pay a bit to have email delivered.
It's not enough. I have a domain that I had a very long time but it is on an undesirable tld. I got it long before it was problematic. Outlook always puts my mail in the SPAM folder even though I have done everything I could. I even deliver through a trusted provider. Not on any spam list. DMARC, DKIM, SPF all set up. No dice.
>Always? If emails are not answered you'll usually notice unless you're a Spammer
Means you're not using your email seriously. For example, to send CVs in response to job postings.
I send up to 20 email per day to people who have issues with their package build scripts, and I have no idea whether they ignore me because they stopped using the distro or because mail got dropped.
Sounds more like using outlook.com is a mistake. I've been running my own mail server for over 20 years and outlook.com is literally the only domain I have had problems with, and this is the only reason that I now send via Scaleway's free transactional email service.
The people working on outlook.com are just talentless amateurs - the rest knows how to do it right. It's a shame it's so widely used.
I don't disagree, but what are your options when a giant portion of the population uses O365 and outlook.com? How are you going to get them to stop using it, so that legit emails from user-owned servers are not silently rejected?
I've also been running my own server for over 20 years, but do note that the big players may block their senders from delivering mail to your server. This happened to me with GMail around 6-7 years ago, until I configured DMARC and/or DKIM and/or SPF to their liking. As far as I know, they don't do a press release when they update their rules.
I have a perfect score in google postmaster tools on dkim, spf and 0 spam reports. They still send all emails to spam. They will even do this if you are replying to the user who contacted you. Same experience for my friend running an indie festival. These days you pretty much have to alert gmail users by some other means (like if signing up on a website) that they have to check spam and whitelist you since it appears gmail would rather block legit emails than allow a single possible spam through.
It depends on the nature of the transaction. If the user needs the email more than you do, you just remind them Outlook deletes your messages, and they'll find a way, and in the long term usage of Outlook will decrease.
outlook.com and O365 are horrible to deliver to. We regularly get issues where we sent an email it was accepted by O365 but was never delivered to the mailbox. We have one person working at least half the time on resolving stuff like that. And that's from a respectably maintained SES egress with good reputation, DMARC, DKIM configured.
Self hosting mail on a shared server in Moldova is basically the entire idea behind email (and the internet).
Which with cheap models like Jev as spam classifiers, this can now become a reality.
The problem is, Google and Microsoft have monopolized the entire email market, so their esoteric deliverability mysticism from 2007 still persists (basically blanket bans on entire IP spaces, locking out anybody trying to send emails on their own).
I was viciously mean in my communication with the Outlook team when they said they “couldn’t” remove me from the blocklist. I pointed out that, as the operator of a perfectly compliant secure server their inability to deliver my mail is a technical failure on their end and one which I will be contacting their supervisor about and they somehow managed to scrabble together the heroic ability to delete my row from a table. Never back down from these bastards.
> Outlook.com and similar are an anathema to email. This is why they tell you not to run a mail server .
It turns out that whoever has the most power is the most powerful. This is why distributed/decentralized systems cannot singlehandedly free us from tyranny, and why I find people who spend all their time preaching decentralized systems to be quite silly. We don't need better systems (well maybe we do but,,,), we need better education and awareness of how billionaires manipulate us; this goes beyond software.
Decentralization is not a bulletproof solution. It is a mitigation. Until someone gets 50 percent of market share. Then they can run havoc on the ecosystem with their own customized system.
Complain all you want about the monopolists, and I do think you're right to do so, but a lot of their power comes from and is aimed at defeating the overwhelming flood of spam.
Mail, then emails, then home phones, then cell phones, then texts, then social media have been gradually rendered less and less usable by bad actors systematically abusing every single tool we try to use to communicate with one another to steal from us, lie to us, and manipulate our beliefs, and we'll just keep inventing and discarding new ways of communicating until we reckon with this.
With cheaper AI classification models coming out every day now, the spam problem is on the cusp of basically being solved in every communication channel.
The only question is how many years the lazy big tech network-effects monopolies (like Google and Microsoft) will hold this back from happening.
The optimist in me says this will unlock pathways to true decentralization of push communication protocols (like SMTP) instead of only have decentralization of pull-oriented protocols (like HTTP).
Generation is, and always will be, cheaper and easier to do well than classification.
AI becoming faster empowers attackers far more than it empowers defenders. We're seeing this in every discipline and every corner of the software industry.
Just put codex in a continuous goal loop to keep you off the blacklists...give it whatever email / creds it needs to make the appropriate requests and make the needed changes (ofc tell it the guardrails it should follow).
Selfhosted email is likely easier now than it ever was before.
I've had several times where mail from custom domains associated with a business were delivered hours late by Outlook. Time sensitive emails. A guy coming to my office for a meeting called me and said he was downstairs and having an issue with security. Went down and swiped him in.
Four hours later, I got the same message by email. I thought he was back - nope. An email sent at 10am that was delivered at 4pm showed it was from 2pm until I looked at the header and saw sent at 10am and just... chilling out for 4 hours. DMARC was set up for them just fine.
I've had the same issue with my own custom domain, with DMARC set up. A year later, it finally got bumped up to some sort of "trusted" domain for that one place and my emails get delivered the same day now.
Pretty sure this or part of this just burned me. Icing on the cake is Nintendo will also ban hammer your email if it rejects some or all of their emails - including their dumptruck of marketing junk. The only and I mean only resolution to this is to basically move your Nintendo account to a different email completely. Absolutely unreal on both sides.
Yes, no one should not have DKIM or DMARC but holy yikes when neither side wants to actually give in to help the customer.
My first thought as well: how does one quietly reject email? Skimmed the comments and clearly it's not quietly. Saved a click...
It's quiet only if the server accepts it and then deletes it on their end without notifying the sender, but if your mail provider shreds your mail that's then also your provider's responsibility and not the sender's
Replying to all inbound messages with a bounce is an old idea. The theory was that legitimate senders would validate their address and get added to a white list. The scheme didn't work for the same reason captchas don't work.
Tangentially-related: Gmail has started sending completely legitimate emails to spam. DMARC/SPF/DKIM (2048 bits) all properly configured of course so there has to be something else that isn't documented.
They have been doing that for years. A long time ago there was a submission here on HN about some Ivy League college urging college applicants to provide something other than a Gmail address because application-related emails (including acceptances!) would frequently not get through.
Started? My Gmail spam filter has been broken for several years now. Extremely obvious spam regularly ends up in the primary inbox and critical, fully legitimate messages get buried in spam. It’s a major reason why I left for another provider.
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[ 1.5 ms ] story [ 44.0 ms ] threadAlthough there seems that there hasn't been any communication which is the bad thing here. However, nobody looks at those and sending detailed emails back seems like a good enough solution.
Email is, I think, among the most distributed popular online services, and there's a ton of stuff that's legacy, self-managed, or otherwise janky. Supporting SPF, DKIM, and DMARC does put a burden on independent operators, but is it an undue or unreasonable one in the current landscape? Or is it just the new cost of doing business?
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.
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.
En contraire, I think not delivering mail is the fastest way to adoption. People will use an old system for as long as it works. It now does not anymore.
Maybe you're right that just enforcing it is the way, but I don't agree with doing that with no heads up.
https://mastodon.social/@davisr/117570496362439342
It's not months it's years.
Good for Microsoft customers and I don't care one bit for the lazy people who have to late-patch now.
https://ciphercue.com/blog/dmarc-enforcement-gap-rua-fragmen...
https://news.ycombinator.com/item?id=49081783
I have MCP servers for the creation of domains, DNS records with DNSSEC, and email accounts with SPF, DKIM and DMARC. I'm sure if someone wants to be a professional spammer today, DMARC is not a differentiator.
Company sys admins have likely got all sorts of other issues to worry about, and the occasional report of an email not getting through is likely low on their to-investigate list.
Having said that, I self host a mail server, and have all those things setup correctly, and my workplace uses Outlook, and I've not had issues with delivery, so it's not a particularly difficult bar to jump.
Go to https://mail-tester.com. Send a test email. If you don't get 10/10, fix your shit.
Some can affordably deliver to Microsoft because they aggressively police what they are actually sending on their customers' behalf; others don't get involved and you end up having to spend a fortune on a dedicated IP.
The DMARC thing is just another part of this; one of my clients discovered this silent failure themselves a few weeks back and addressed this.
DMARC applies not on your mail server, inbound or outbound, but on the server that is receiving your mail (which may in fact be your mail server).
That server will look at how the mail authenticates and decide if it should allow the mail to proceed, it (for the most part) will then tell you whether or not it allowed the mail. This is how you will know you might have a deliverability problem before your customers do.
If you're wanting to know about deliverability (particularly for this Microsoft case), my company (Alesian Security) has a free check at https://alesiansecurity.com/try?tab=deliverability
It's been a while, but monitoring DMARC seemed pointless once you got things started. If my outbound mail fails to validate, I've asked the receivers to bounce it, and I should be able to see that on my own system.
Otherwise, I'm just getting reports about spoofed spam or people who need to adjust their mail forwarding, but I can't do anything about either.
But it provides a safe guard against accidentally broken mail flows as your email stack evolves over time which is where it pays dividends.
I would love to say that it would have alerted you ahead of time to this particular event, but given that it's the fix here you would never have seen it.
It doesn't prevent spoofing, it doesn't say which IPs are authorized to send on behalf of a domain, it doesn't sign messages. Spoofed messages are still sendable.
Can you explain the benefit of only accepting email if Microsoft knows that you may or may not accept emails about scammers unsuccessfully spoofing your email domain? (Note, there's nothing you can do if they do tell you.)
Don't confuse DMARC with DKIM or SPF; DMARC doesn't actually do anything for email security.
"Oh, please, don't ignore the other two ways I told you to ignore unauthorized messages" shouldn't need a knob.
You get an email without a DKIM signature from me.
Is that because I do not use DKIM and do not sign my emails or because the message is forged and not from me at all?
You cannot tell. There is a single SPF record that you can look up to see if SPF is configured. It's just a TXT record on the domain. But there is no standard DKIM record. A DKIM signed email tells you what key identifier it used and you have to use that to look up the DKIM key at <key identifier>._domainkey.<sender domain>. When the email has no DKIM signature you cannot tell if that's because the sender domain does not use DKIM or if it does have a DKIM key record but it was not used, potentially because the email is forged.
gmail runs with p=none
so tell me what benefits that has over having no dmarc record at all ?
They did: https://techcommunity.microsoft.com/blog/microsoftdefenderfo...
And it appears to be further documented here:
https://learn.microsoft.com/en-us/defender-office-365/anti-p...
https://learn.microsoft.com/en-us/defender-office-365/email-...
And other sites were reporting about it for at least a year and a half:
https://powerdmarc.com/dmarc-outlook-email-authentication/ (see #4)
https://www.mailreach.co/blog/outlook-dmarc-requirements
That's an old announcement about a different change. As far as I can tell this one is completely out of the blue. I'm shocked by the number of people in this thread advocating for spontaneous changes without any warning.
Not true, at least in my experiences.
I have a bunch of email accounts which have SPF and DKIM, but are missing the DMARC line - I've had no deliverability problems at all, until this weekend, and now only with Outlook. Emails to Gmail accounts go through just fine.
The combination of: √ Valid SPF √ Valid DKIM signature X Missing DMARC policy
Is clearly ambiguous. Since a DMARC of "p=none" (in the context of valid SPF and DKIM) really adds no information, so interpreting "missing DMARC" as "p=none" seems reasonable. Sounds like Microsoft was taking that approach until this weekend.
I wonder if there's an actual written standard?
Most receivers have chosen to treat this as p=none for the last decade (Microsoft included). This is changing to now so that mail with no record is simply refused. Nothing in the standard prohibits this.
a DMARC of p=none might be seen as ambiguous - SPF and DKIM have their own jobs and they work. However, the point of DMARC is not a new way of enforcing mail authentication. Instead it is a way of making certain that the mail is internally consistent and furthermore provides two additional things.
1. it indicates if the domain owner has thoroughly gotten their mail to authenticate (in which case they adopt a p=reject), and
2. it provides a feedback mechanism that allows the domain owner to know if they are seeing authentication and deliverability problems in such a way that they can fix those broken mail flows.
[1] https://www.rfc-editor.org/info/rfc7489/
Just not for this.
I had kinda assumed that a lot of providers would start rejecting domains without DMARC support. I'm surprised it's happening this late.
When I ran that server, outlook.com was also the only one that would blackhole my email for no known reason. Support was unhelpful and also could not point to any reason. I've since given up, but for a short time it was glorious, email to family would not leave the lan and we could send attachments of arbitrary size.
[0] https://news.ycombinator.com/item?id=7708882
Is there a risk some people on this thread are mixing up DKIM and DMARC?
DKIM = proving that an email was sent from a specific domain using cryptography. Good for spam fighting and deliverability.
DMARC = telling receivers how to handle mail that fails authentication.
DMARC is primarily useful for large, complex organizations where email admins may not be aware of everyone inside the org who is sending mail that advertises the domain in the From header, or organizations that might be targeted by impersonation attacks (e.g. phishing). Being able to tell recipients "yes we absolutely have our act together so feel free to reject or spamfolder unauthenticated email" is great for killing phishing campaigns, and being able to request reports is great for finding that one sales org that signed up for a guerrilla marketing SaaS that's impersonating them.
But for small personal domains the value isn't that high.
No. DMARC is about if the from address has to match the address used in dkim/spf
A specification exists since 2012, 14 years ago. 10 years ago it was already old.
Back then, I didn’t use Terraform or anything like that, but I had text files with logs that described the DNS setup in detail so I could fix things. By grepping through the logs, I’m able to put a definitive bound on when I added DMARC—it was no later than June 2016, over 10 years ago.
At the time I thought, “Obviously, we should all be setting this up, because recipients will start rejecting mail from insecure domains, if they don’t already.” This was also back when I self-hosted email. I eventually stopped doing that because I thought it was too time-consuming.
>But for small personal domains the value isn't that high.
I don't understand the resistance. It benefits the entire mail ecosystem, not just mass senders.
SPF used to be niche thing, then everyone realised it's a good idea and it became more-or-less mandatory. Same with DKIM. Now it has happened to DMARC as well.
10 years is nothing. I'm sure there's still millions of companies globally who still aren't properly signing mail with DMARC.
maybe someone was too lazy to set up "inbound block list" and just did a total blackout instead?
Sounds like kind of a hack:
"ARC was devised to solve this problem by giving intermediate servers a way to sign the original message's validation results. Even if the SPF and DKIM validation fail, the receiving service can choose to validate the ARC chain. If it indicates that the original message passed the SPF and DKIM checks, and the only modifications were made by intermediaries trusted by the receiving service, the receiving service may choose to accept the email."
Outlook.com and similar are an anathema to email. This is why they tell you not to run a mail server .
On the other hand rejecting domains without dmarc is fine. Just not happy it is silent.
At the most you need to use an external service for delivery (usually because you have problems with MS) but you can still run your own server with no difficulties once you do that.
That said, DMARC is required by a lot of people now, so I do not think this particular issue is a problem.
I have been self hosting my my personal email (and for family). Few problems so far other than delivery to MS and I have recently moved a domain I use for work email over.
Oddly enough the MS problems come from hotmail, but not other services. If that is a problem, then pay a bit to have email delivered.
Means you're not using your email seriously. For example, to send CVs in response to job postings.
I send up to 20 email per day to people who have issues with their package build scripts, and I have no idea whether they ignore me because they stopped using the distro or because mail got dropped.
You should be able to see this on your DMARC dashboard
The people working on outlook.com are just talentless amateurs - the rest knows how to do it right. It's a shame it's so widely used.
Most of them wouldn't even care probably...
What about tencent.com, foxmail.com, or qq.com?
Fortunate for those running their own servers is that they actually still get all the cool emails from people not complying.
It's always people self-hosting mail on a shared server in Moldova (because they think it makes them cool) that are complaining.
https://www.mimar.rs/blog/a-journey-of-my-mx-server-to-new-r...
And yes, it's cool not to have to let scum read your private communications :D
Which with cheap models like Jev as spam classifiers, this can now become a reality.
The problem is, Google and Microsoft have monopolized the entire email market, so their esoteric deliverability mysticism from 2007 still persists (basically blanket bans on entire IP spaces, locking out anybody trying to send emails on their own).
With LLMs on the other side trying to make spam less detectable by cheap models like Jev?
It's funny when people assume benefits from some tech go one way and baddies will surely never use it...
It turns out that whoever has the most power is the most powerful. This is why distributed/decentralized systems cannot singlehandedly free us from tyranny, and why I find people who spend all their time preaching decentralized systems to be quite silly. We don't need better systems (well maybe we do but,,,), we need better education and awareness of how billionaires manipulate us; this goes beyond software.
Mail, then emails, then home phones, then cell phones, then texts, then social media have been gradually rendered less and less usable by bad actors systematically abusing every single tool we try to use to communicate with one another to steal from us, lie to us, and manipulate our beliefs, and we'll just keep inventing and discarding new ways of communicating until we reckon with this.
The only question is how many years the lazy big tech network-effects monopolies (like Google and Microsoft) will hold this back from happening.
The optimist in me says this will unlock pathways to true decentralization of push communication protocols (like SMTP) instead of only have decentralization of pull-oriented protocols (like HTTP).
AI becoming faster empowers attackers far more than it empowers defenders. We're seeing this in every discipline and every corner of the software industry.
But we won't.
So that people would vote for the government to manipulate them instead?
Honestly, I hate outlook as much as you do, but I'd still prefer it to Max
https://en.wikipedia.org/wiki/Max_(app)
Selfhosted email is likely easier now than it ever was before.
This is not Microsoft's fault. The building's on fire and they're locking out the arsonists.
Four hours later, I got the same message by email. I thought he was back - nope. An email sent at 10am that was delivered at 4pm showed it was from 2pm until I looked at the header and saw sent at 10am and just... chilling out for 4 hours. DMARC was set up for them just fine.
I've had the same issue with my own custom domain, with DMARC set up. A year later, it finally got bumped up to some sort of "trusted" domain for that one place and my emails get delivered the same day now.
Yes, no one should not have DKIM or DMARC but holy yikes when neither side wants to actually give in to help the customer.
> The sender gets a bounce
?
It's quiet only if the server accepts it and then deletes it on their end without notifying the sender, but if your mail provider shreds your mail that's then also your provider's responsibility and not the sender's
I haven’t really seen BIMI for less than practically $1000/year and most clients still don’t check it.
(dmarc only requires one of spf or dkim, not both, but it is a good idea to use both)
Oh god the slop.
Only an LLM would describe DMARC as just "one DNS record".