DMARC adoption trends: Q3-Q4 2023

It's time for some more fun with data!

How broadly has DMARC been adopted? It's a complex question and the answer is "it depends." Many good senders have already implemented it -- but based on Yahoo and Google pushing for it this year, it has clearly not been adopted widely enough for it to be considered a "must have" for every domain that sends mail. (And let's not forget about domains that don't send mail.)

Every month, I take a peek at the top 10 million domains, logging various bits of DNS so that I can do later analysis. One of those data bits is: Does this domain have a DMARC record? Surprisingly, you can't assume that the answer is yes. Though you can see that DMARC adoption is slowly nudging upward, only around 1.23 million domains (out of the top ten million) have a DMARC record in play.

Now...this methodology can be a bit questionable. Though I stand by it as it's not easy to just broadly measure the Internet, it has its limitation. Updating what constitutes the "top 10 million" periodically is probably what resulted in a bit of a glitchy drop in records found between August and September. I wasn't sure how best to handle that -- but now I think the best thing I can do is continue to update the top 10 million periodically and recognize that we're looking for broad trends over time, and those glitches come out in the wash.

Also, what constitutes the top 10 million? This isn't based on email traffic -- but web traffic and other stuff. As mentioned before, since I don't have big iron MTAs at my disposable to extract domain data from, I've got to look elsewhere. And there are various lists of "top domains" out there, including this one from

Even with limitations, this data is really fun to watch. The million dollar question, is, of course, will DMARC adoption explode in 2024? I suspect so, thanks to the new Yahoo Mail and Gmail sender requirements, and I'm excited to be able to watch and see if that is borne out from this data.

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