DMARC Has Been Public Since 2012. 68.4% of Domains Still Don't Enforce It
Posted by adulion 7 hours ago
Comments
Comment by bcrl 4 hours ago
The core problem is that the real need of email end users need is a way of determining whether or not to trust a given sender. Signatures are purely a technical measure which provides no information on the trustworthiness of the sender. The end result is that email scoring still has to be content based, and the signature check technologies are pure noise with no useful signal for the purpose of determining if an email should actually show up in my inbox.
The tech industry has a bad habit of providing solutions to problems adjacent to problems the user actually needs solved while leaving the user's actual problem unresolved.
Comment by bawolff 3 hours ago
Which is only the core problem because dmarc fixed the other core problem of figuring out who the given sender is.
DMARC does not solve everything, but it does make other solutions more effective.
Comment by brightball 2 hours ago
This should create a means to go after the domain owners via registrar and trail of ownership, even so far as blocking email from the domain.
Forcing the spammers to pass DMARC creates a burden and an evidence trail that didn't exist before.
Comment by WorldMaker 45 minutes ago
It feels like the biggest spammers have swung back to just abusing SaaS and getting SPF / DKIM / DMARC for free from one of the big email providers.
Comment by bigbuppo 1 hour ago
Comment by thedougd 2 hours ago
Comment by HenriTEL 1 hour ago
Comment by wafflebot 1 hour ago
Comment by warkdarrior 1 hour ago
Comment by daneel_w 1 hour ago
Comment by kbolino 1 hour ago
Comment by zahrc 30 minutes ago
Using it minimally is correct, thou. Route outbound mail through as few controlled relays as possible so your SPF record only needs to list infrastructure you actually *own*, rather than growing it every time a new tool needs to send mail.
I have seen way too many clients almost hit the char limit in a TXT record
Comment by kbolino 6 minutes ago
I would certainly agree that DKIM is harder to get right. However, the TXT record data size limit is surmountable. You can either use EC algorithms, which have much shorter keys, or stick with e.g. RSA and its very long keys, but span them across multiple 255-byte record data chunks. That having been said, I still think DNS providers should do more to make configuring DKIM easier.
Ultimately, if you have both SPF and DKIM set up "properly", then you are just using SPF. It is the simpler and more forgiving mechanism, so its broad-scoped successes will always swallow DKIM in practice. The only reason I can think of to do this anyway is if you suspect your email provider will change IPs on you and they don't provide their own SPF record, but if that were the case, they are basically telling you not to use SPF in the first place.
[1] = https://datatracker.ietf.org/doc/html/rfc7489#section-4.2
Comment by aaronmdjones 1 hour ago
Comment by egorfine 2 hours ago
Extremely well said.
Comment by newsoftheday 3 hours ago
Comment by SoftTalker 2 hours ago
Comment by matharmin 2 hours ago
Now if the sender used SPF + DMARC but not DKIM, this does not work, since the sender IP can't be verified with the forwarded email. In that case, the forwarder has to change the from address to prevent the email from failing DMARC and be rejected.
In practice, senders using SPF+DMARC but not DKIM should be quite rare, you see DKIM+DMARC much more often.
Comment by Polizeiposaune 1 hour ago
I've often seen messages resent by Microsoft's mail infrastructure with gratuitously broken DKIM signatures, generally due to changes to whitespace that are not anticipated by DKIM's message canonicalization.
I've also seen messages sent by my bank directly to the email system I administer that had broken DKIM signatures apparently due to some sort of antivirus software they had downstream of the DKIM signer.
Comment by ryanbrunner 1 minute ago
Comment by matharmin 46 minutes ago
Comment by cookiengineer 3 hours ago
Additionally, I would probably guess correctly that almost all spam comes from rotating ASNs these days. Aka from companies that do "growth marketing" or other bullshit that isn't a valid business but just... spamming people.
A lot of the domains that fall through the cracks for single-spam-campaigns have been taken over by botnet campaigns, so the actual owners of said domains probably don't know that their website is spamming everyone else.
But the major providers are the culprit, too, here. Gmail, hotmail, microsoft o365, mailgun ... they all don't even enforce SSL from server to server, and let through "sendmail" like spam because the spammers are paying customers to them.
Source: I am maintaining antispam [1] which I am using to combat spam, phishing, and malware campaigns targeting my customer networks.
Comment by EvanAnderson 4 hours ago
Comment by velcrovan 3 hours ago
Comment by EvanAnderson 2 hours ago
More often than not I end up talking to someone in the sender's IT who fancies themself an expert and is completely incredulous that there could possibly be a problem on their side ("But we don't have problems sending email to anybody but you...")
I should want to fight the good fight, but it's so demoralizing.
Edit:
Dealing with other IT people on problems like this taught me a ton of humility. It wasn't until I was in my early 30s before I'd reached a level of maturity to approach trouble reports like this being reported to me with an open mind. Before that I fancied myself and expert and, likely, was insufferable in many contexts.
Now I'm insufferable in fewer contexts.
Comment by account42 2 hours ago
Comment by drdexebtjl 1 hour ago
Comment by TheChaplain 4 hours ago
DNS SPF record: mydomain.io. TXT "v=spf1 -all"
DNS DMARC: _dmarc.mydomain.io. TXT "v=DMARC1; p=reject; sp=reject; adkim=s; aspf=s"
That ought to stop anyone trying to use your domains as source.
Comment by brightball 2 hours ago
It would solve a lot of issues globally.
Comment by teddyh 3 hours ago
*.mydomain.io. TXT "v=spf1 -all"
to restrict SPF on all subdomains.Comment by newsoftheday 3 hours ago
admin@example.com OK postmaster@example.com OK abuse@example.com OK webmaster@example.com OK hostmaster@example.com OK info@example.com OK example.com REJECT example.com
Comment by talkingtab 4 hours ago
If you decide to think about this, you will quickly realize that email is f*ked and needs to be forked. Perhaps we need a Community Email Initiative that blocks corporations and only allows Community members.
Trust is the one thing you can't buy on the Corporate Internet.
I am sure many people will be offended and down vote this comment because they cannot conceptualize an internet without Corporations.
Comment by baron3dl 4 hours ago
Depending on how hard you want to make it, you can slap all the parts together yourself or use something like Zimbra, Mailcow, iRedMail, mail-in-a-box.
The advantage over a fork, whatever specifically that means, is any service that needs E-mail as an identity verification, still works.
Comment by wolvoleo 2 hours ago
It's time for a new protocol with end to end encryption and sender verification built-in. That shouldn't be as hard as it sounds, because at the time when email was invented the internet was very different. Connections were intermittent, for example I would retrieve my email once a day with UUCP (and some other people would use batched-SMTP). Which means you could not rely on the sending and receiving server being able to communicate directly. In this day and age this is possible and that direct communication opens up a lot of better crypto like key generation algorithms which require both parties to be online at the same time.
The problem is, is you don't allow corpos you will break 95% of mainstream people's usecases. So I think this is a non-starter, unfortunately, though it is a lofty goal.
Comment by thesuitonym 3 hours ago
There is so much crossover between personal email and corporate email.
Comment by dmurray 2 hours ago
Comment by account42 2 hours ago
Comment by 1over137 4 hours ago
Comment by onraglanroad 1 hour ago
Have your own gmail.com
Comment by tgv 5 hours ago
Comment by infogulch 3 hours ago
Some changes I made at the direction of an agent: fix domainkeys CNAMEs for M365, rotate M365 dkim keys that haven't been rotated for over a decade, fix broken spf record formatting.
My biggest issue is that squarespace refuses to enable dkim signing for transactional emails that they send for us (order/shipping confirmation etc). The email sending service they use (socketlabs) supports it but they are not interested in enabling the feature, so I can't lock down our dmarc. I guess that means squarespace is not a good fit for our needs; it's just disappointing that we have to move to a different platform again for technical reasons that are solvable with a dashboard switch.
Comment by tgv 2 hours ago
Comment by jwr 4 hours ago
The big companies do not have to care because nobody will block Google, Microsoft or Amazon. They are too big to fail.
Spoofing a From field is an insignificant problem in comparison.
Comment by thesuitonym 3 hours ago
Comment by cube00 4 hours ago
I even go to the trouble of registering in their Postmaster Tools and clogging up my DNS with their verification tokens all for the tools to tell me I don't send enough mail while they happily pass what little mail I send straight to spam.
Not enough outgoing email
You haven't sent enough email to personal Gmail (@gmail.com) accounts to determine deliverability status for your domain and messages.
Each screen only shows: "No data was found for this domain."Guess it doesn't help that as I look today the Postmaster Tools dashboard shows "Last updated Sun, Apr 26, at 9:30 AM."
Then on the other hand Google can flood me with spam filled Google Calendar Invites and Google Drive Share notifications, all fully DKIM signed because they are coming out of those services, all day long.
Microsoft have also recently changed their Smart Network Data Service (SNDS) so now only my cloud provider can access the console as they only allow verification to the owner of the whole ASN block you're under. I can't access detail about my domain anymore, and still my mail goes to junk. Unless you own a chunk of IPv4 ASN range you're out of luck. IPv6? Nope, not at Microsoft. "Please note that IPv6 is not currently supported." [1]
[1]: https://substrate.office.com/ip-domain-management-snds/SNDS/...
Comment by newsoftheday 3 hours ago
And I can Remove or Renew Access, or those links are showing.
Comment by butterknife 4 hours ago
Comment by draygonia 3 hours ago
Comment by account42 2 hours ago
Comment by account42 2 hours ago
Comment by TonyTrapp 2 hours ago
Comment by agotterer 1 hour ago
Comment by raluk 3 hours ago
Comment by matharmin 3 hours ago
But if you send all emails for your domain from one email server, you could just disable rua reporting. The reports are mainly useful to see whether you have some misconfigired email server somewhere that causes (or will cause) dropped emails. That can easily happen if you send some email from your own server, some via sendgrid, some via some marketing tool, and start to lose track of them. But for a personal email server, that's not common.
Comment by toast0 2 hours ago
Comment by nubinetwork 4 hours ago
Comment by vandyswa 4 hours ago
Comment by at1as 2 hours ago
The latter are likely to adopt much more slowly simply because of less perceived risk, lower payoff (no vendor reviews), and less dedicated technical expertise.
Just like personal sites were slow to adopt HTTPS. Mass HTTPS adoption happened once browser warnings and SEO incentives rendered sites mostly useless without it.
Comment by account42 2 hours ago
Comment by rft 4 hours ago
Comment by account42 2 hours ago
Comment by smartmic 5 hours ago
Comment by bawolff 3 hours ago
Comment by cube00 4 hours ago
Some mail providers will junk your mail if you don't have a reject/quarantine DMARC policy because you're seen as enabling the spammers so everything out of your domain must be punished.
Comment by asimpletune 5 hours ago
Comment by comrade1234 5 hours ago
Comment by kamma4434 5 hours ago
Comment by thesuitonym 3 hours ago
Comment by winstonwinston 4 hours ago
For example, gmail.com treats unauthenticated email as spam implicitly, regardless of DMARC policy.
Comment by azeemba 5 hours ago
The report that they send you is useful for you to make sure your emails that you expect to go through are going through.
Comment by toast0 2 hours ago
Comment by AshamedCaptain 5 hours ago
Comment by aaronmdjones 53 minutes ago
In the following SMTP conversation:
MAIL FROM: foo@example.net
RCPT TO: victim@example.com
DATA
From: service@paypal.co.uk
To: victim@example.com
Subject: We are updating our Terms of Service
[...]
SPF checks whether the sending host is allowed to send e-mail from example.net (the envelope sender).The recipient sees service@paypal.co.uk (the From address on the inner message), because most ESPs do them the great disservice of not indicating that the sender identities are not aligned.
Adding a DMARC record to a domain requires that e-mail whose inner messages claim to be from that domain must have sender alignment to the envelope sender.
The above message would pass SPF (if the spammer owns example.net and has created SPF records for themselves) but would fail DMARC (paypal.co.uk's DMARC record exists, so alignment is required, and yet example.net != paypal.co.uk, so they are not aligned). In this case their DMARC policy says to reject the message, so (if the recipient is checking DMARC) it would either be rejected outright or it would land in Spam/Quarantine rather than Inbox.
Comment by ivlad 4 hours ago
SPF allows to say “these IPs are authorised to send emails as example.com”, where DMARC allows to say “I as domain owner recommend to quarantine emails that fail SPF and DKIM”, it also allows finer alignment (ie, matching between different “from” parameters) configuration and reporting by the receivers.
Of course, with absence of DNARC policies, receivers default to some internal defaults, or may ignore the policies altogether. But at least, the big ones send DMARC reports.
Comment by wolttam 4 hours ago
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Comment by ButlerianJihad 4 hours ago
https://utcc.utoronto.ca/~cks/space/blog/spam/DMARCPractical...
Comment by sebow 3 hours ago
Anyways, the new CF AI tool is relatively decent for this purpose, explains the fact that most warnings in CF are harmless, but the lack of standardized guidelines is annoying to say the least.
Comment by thomas_krosos 2 hours ago
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