Sadly the article doesn't really touch on whether or not DMARC accomplishes anything truly useful. When I enabled DMARC for ingress email on one of my own mail servers, it ultimately ended up regularly blocking a handful emails from customers, yet virtually all the spam coming in had valid SPF / DKIM / DMARC, as do most of the phishing attacks.
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.
My domain is very low traffic but, I just looked through my admin email account and opendmarc has rejected 18 attempts by spammers just this past week. More were rejected by my domain's DMARC policy.
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.
I mind email for a number of small orgs (<1000 recipients each). There are so many SPF and DKIM failures from senders who you'd think would know better (Fortune 100-type companies). I don't want complaints from users missing messages so I end up disregarding failures even when published policy says to do otherwise.
I use postfix and the recipient_access file to control email to my domains which use little email, so the domains are able to process standard email:
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
Email has been turned into a by-the-corporation, for-the-corporation service. Corporations need DMARC so they can control email and the ability to spam. The spam I cannot block is spam from Google.
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.
You can do this right now, and you don't even need to fork anything. E-mail is an internet scale protocol that's not owned or ownable, except by convention. Since you specifically want to cut out Google, and their attempts to capture E-mail are what makes rolling your own E-mail hard anyway, just go for it.
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.
You can already do this without changing anything. Just set your corporate mailserver to not accept mail from common community email providers. There's a reason nobody does this, and it's because it's a bad idea.
There is so much crossover between personal email and corporate email.
The article speaks about DMARC monitoring, but not about "writing" it. So many orgs are too small to have someone paying attention of these things. Where I work, the CTO used to manage the DNS, but with very little understanding of what it all means. It was just copy and paste. And yes, it also says p=none. Probably because it was in the example. It's like setting up a website for your company, and picking some wordpress instance: how are you supposed to know the risks? It's just too much.
LLMs are very good at helping you manage DMARC/DNS related configuration, even as a non-expert. I used it to develop custom DMARC report processing app that: 1. sucks in reports sent to our dmarc inbox into a sqlite db, 2. displays the results in a web page. The reports queue up in the mailbox and I open and start the app once a month to check the status. The agent also also reviewed the state of email-related DNS records, describe what needs to change, including how and why, and verify changes after the fact to ensure they are correct.
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.
I am running email server for my private domain using https://github.com/docker-mailserver/docker-mailserver . One day in 2023 i decided that beside of dkim i maybe should also enable dmarc. Because ... well, why not. What happened was that i started reciving regular reports over email from ms and google containing compressed xml containing no info other that empty report was generated. What should I do with that? At that time i could not find any tool that would be able to extract valuable info from that, so I disabled dmarc. Havent looked back since.
There are lots of free tools that automatically analyze the reports for you (you send it to them, instead of yourself).
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.
I really think we should be solving a much bigger problem of the major email providers not providing an automated way of handling abuse and not caring about abuse reports at all. Most of my spam comes from the three major email providers and at this point I gave up even trying to send abuse reports because they just get ignored.
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.
It's ironic that I set everything up correctly on my self hosted domain and still end up in spam because of my low volume.
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]
In the same boat here. At least still have a good standing at Microft. Lost goodwill at big G by what I vaguely narrowed down to self hosted images in e-mail signature.
DMARC, just like SPF before it, solves nothing. The spammers adapt. And unlike SPF, DMARC has an enormous technology surface area. Its failure modes are legion, and each one is tedious to run down to resolution. Which just returns you to something which never pays the rent anyway.
Article is missing a note on the existence of MX records for the domains. Sure, you can easily have a send-only domain without an MX record, but the common case is likely to setup both send and receive capability. It would be interesting to have that number included as domains without MX and DMARC might just not be configured for email at all. Worst case the 45% of domains without DMARC are simply not relevant for email and thus not configured at all. I would find "x% of domains with configured email don't enforce DMARC" more interesting.
I am self-hosting my (secondary) email and have only implemented SPF and DKIM. This works fine on a practical level for me. What would be the benefit of setting up DMARC on top?
> What would be the benefit of setting up DMARC on top?
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.
Google, Microsoft, Amazon and others send me summary reports of people spoofing my domains. I have dmarc set for them to accept the email, mark it spam (presumably) and send me a report. I really should and can tell them to reject the spam completely - another setting in dmarc but haven't yet out of laziness basically.
Realistically spoofed address (unauthenticated email) will be treated as spam and it’ll be implicitly quarantined or rejected as such by many well-known mail receivers. You can make this an explicit “reject” by publishing DMARC policy for your domain.
For example, gmail.com treats unauthenticated email as spam implicitly, regardless of DMARC policy.
`p=reject`, ESPECIALLY for your personal email. `p=quarantine` is really only useful if you suspect your marketing department has set up some email blaster somewhere.
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.
Not always. An email has a valid SPF when its return path email’s domain permits the sending server’s IP. But that email may have a forged From: header (which causes an SPF mis-alignment), and the receiving server checks the DMARC of *the From header* domain to determine how to handle that mis-alignment.
DMARC is essentially an opt-in to strict mode. Primarily it prevents other people from forging email to look like it is coming from you. The goal of dmarc is to prevent other people from impersonating you.
The biggest benefit I saw in a small domain was greatly reduced backscatter spam. Before someone’d randomly make up a billion emails on my domain and send “from” them, and I’d get various out of office replies, etc (catch all) - that basically never happens anymore.
DMARC is simple in theory but quite tricky in practice (with subdomains, for example).
You follow the guide for a service (say Mailgun, for example) and everything looks fine, but CloudFlare shows up issues. You fix those issues and you're conflicting the mail service guide.
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.
Sadly the article doesn't really touch on whether or not DMARC accomplishes anything truly useful. When I enabled DMARC for ingress email on one of my own mail servers, it ultimately ended up regularly blocking a handful emails from customers, yet virtually all the spam coming in had valid SPF / DKIM / DMARC, as do most of the phishing attacks.
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.
> 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.
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.
My domain is very low traffic but, I just looked through my admin email account and opendmarc has rejected 18 attempts by spammers just this past week. More were rejected by my domain's DMARC policy.
^ this
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.
[1] https://github.com/cookiengineer/antispam
I mind email for a number of small orgs (<1000 recipients each). There are so many SPF and DKIM failures from senders who you'd think would know better (Fortune 100-type companies). I don't want complaints from users missing messages so I end up disregarding failures even when published policy says to do otherwise.
If you have any domains that does not use email, it may be a good idea to set up some DNS records to prevent it being used.
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.
I use postfix and the recipient_access file to control email to my domains which use little email, so the domains are able to process standard email:
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
Email has been turned into a by-the-corporation, for-the-corporation service. Corporations need DMARC so they can control email and the ability to spam. The spam I cannot block is spam from Google.
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.
You can do this right now, and you don't even need to fork anything. E-mail is an internet scale protocol that's not owned or ownable, except by convention. Since you specifically want to cut out Google, and their attempts to capture E-mail are what makes rolling your own E-mail hard anyway, just go for it.
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.
You can already do this without changing anything. Just set your corporate mailserver to not accept mail from common community email providers. There's a reason nobody does this, and it's because it's a bad idea.
There is so much crossover between personal email and corporate email.
What do you mean “fork”? Just buy a domain and install an email server.
The article speaks about DMARC monitoring, but not about "writing" it. So many orgs are too small to have someone paying attention of these things. Where I work, the CTO used to manage the DNS, but with very little understanding of what it all means. It was just copy and paste. And yes, it also says p=none. Probably because it was in the example. It's like setting up a website for your company, and picking some wordpress instance: how are you supposed to know the risks? It's just too much.
LLMs are very good at helping you manage DMARC/DNS related configuration, even as a non-expert. I used it to develop custom DMARC report processing app that: 1. sucks in reports sent to our dmarc inbox into a sqlite db, 2. displays the results in a web page. The reports queue up in the mailbox and I open and start the app once a month to check the status. The agent also also reviewed the state of email-related DNS records, describe what needs to change, including how and why, and verify changes after the fact to ensure they are correct.
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.
I am running email server for my private domain using https://github.com/docker-mailserver/docker-mailserver . One day in 2023 i decided that beside of dkim i maybe should also enable dmarc. Because ... well, why not. What happened was that i started reciving regular reports over email from ms and google containing compressed xml containing no info other that empty report was generated. What should I do with that? At that time i could not find any tool that would be able to extract valuable info from that, so I disabled dmarc. Havent looked back since.
There are lots of free tools that automatically analyze the reports for you (you send it to them, instead of yourself).
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.
I really think we should be solving a much bigger problem of the major email providers not providing an automated way of handling abuse and not caring about abuse reports at all. Most of my spam comes from the three major email providers and at this point I gave up even trying to send abuse reports because they just get ignored.
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.
Email providers do have an automated way of handling abuse. Send the message to abuse@provider and they automatically ignore it. =)
It's ironic that I set everything up correctly on my self hosted domain and still end up in spam because of my low volume.
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.
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/...
In the same boat here. At least still have a good standing at Microft. Lost goodwill at big G by what I vaguely narrowed down to self hosted images in e-mail signature.
DMARC, just like SPF before it, solves nothing. The spammers adapt. And unlike SPF, DMARC has an enormous technology surface area. Its failure modes are legion, and each one is tedious to run down to resolution. Which just returns you to something which never pays the rent anyway.
I'll set up DMARC after I get DKIM working... migrating my homelab has been taking forever...
Domains with stricter DMARC that isn't on 'none' are in my experience more likely to be spammers than desirable email.
Article is missing a note on the existence of MX records for the domains. Sure, you can easily have a send-only domain without an MX record, but the common case is likely to setup both send and receive capability. It would be interesting to have that number included as domains without MX and DMARC might just not be configured for email at all. Worst case the 45% of domains without DMARC are simply not relevant for email and thus not configured at all. I would find "x% of domains with configured email don't enforce DMARC" more interesting.
68.4% is actually a lot. Considering how badly abused email has always been, I'm actually surprised its nearly 70% and growing. Cup half full I guess
68.4% still don't enforce it, i.e. adoption is just over 30%, not nearly 70%.
I am self-hosting my (secondary) email and have only implemented SPF and DKIM. This works fine on a practical level for me. What would be the benefit of setting up DMARC on top?
> What would be the benefit of setting up DMARC on top?
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.
Because if someone spoofs an email coming from your domain DMARC tells the receiver what to do with the spoofed email.
Google, Microsoft, Amazon and others send me summary reports of people spoofing my domains. I have dmarc set for them to accept the email, mark it spam (presumably) and send me a report. I really should and can tell them to reject the spam completely - another setting in dmarc but haven't yet out of laziness basically.
And what is the sane way to handle a spoofed email?
Realistically spoofed address (unauthenticated email) will be treated as spam and it’ll be implicitly quarantined or rejected as such by many well-known mail receivers. You can make this an explicit “reject” by publishing DMARC policy for your domain.
For example, gmail.com treats unauthenticated email as spam implicitly, regardless of DMARC policy.
`p=reject`, ESPECIALLY for your personal email. `p=quarantine` is really only useful if you suspect your marketing department has set up some email blaster somewhere.
That's what the policy setting tells the recipient. You can tell them to trest it as normal, send it to spam or delete it.
The report that they send you is useful for you to make sure your emails that you expect to go through are going through.
And SPF doesn't?
Technically, no.
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.
Not always. An email has a valid SPF when its return path email’s domain permits the sending server’s IP. But that email may have a forged From: header (which causes an SPF mis-alignment), and the receiving server checks the DMARC of *the From header* domain to determine how to handle that mis-alignment.
DMARC is essentially an opt-in to strict mode. Primarily it prevents other people from forging email to look like it is coming from you. The goal of dmarc is to prevent other people from impersonating you.
The biggest benefit I saw in a small domain was greatly reduced backscatter spam. Before someone’d randomly make up a billion emails on my domain and send “from” them, and I’d get various out of office replies, etc (catch all) - that basically never happens anymore.
Using DMARC information is complicated in practice in the real world, by Chris Siebenmann
https://utcc.utoronto.ca/~cks/space/blog/spam/DMARCPractical...
DMARC is simple in theory but quite tricky in practice (with subdomains, for example). You follow the guide for a service (say Mailgun, for example) and everything looks fine, but CloudFlare shows up issues. You fix those issues and you're conflicting the mail service guide.
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.