Datasets:

domaincanary
/

dmarc-census

edition stringdate 2026-08-01 00:00:00 2026-09-01 00:00:00	tranco_list_id stringclasses 2 values	metric stringlengths 9 30	count int64 343 1M	denominator int64 469k 1M	denominator_label stringclasses 4 values	share_percent float64 0.03 100
2026-08	JZ8PY	domains_scanned	1,000,766	1,000,766	domains scanned	100
2026-08	JZ8PY	domains_measured	1,000,296	1,000,766	domains scanned	99.95
2026-08	JZ8PY	dmarc_lookup_failed	470	1,000,766	domains scanned	0.05
2026-08	JZ8PY	dmarc_record_published	474,544	1,000,296	measured domains	47.44
2026-08	JZ8PY	dmarc_record_valid	469,415	1,000,296	measured domains	46.93
2026-08	JZ8PY	policy_none	234,444	1,000,296	measured domains	23.44
2026-08	JZ8PY	policy_quarantine	116,806	1,000,296	measured domains	11.68
2026-08	JZ8PY	policy_reject	118,165	1,000,296	measured domains	11.81
2026-08	JZ8PY	tier_none	525,752	1,000,296	measured domains	52.56
2026-08	JZ8PY	tier_broken	5,129	1,000,296	measured domains	0.51
2026-08	JZ8PY	tier_dead	128,980	1,000,296	measured domains	12.89
2026-08	JZ8PY	tier_monitoring	105,464	1,000,296	measured domains	10.54
2026-08	JZ8PY	tier_partial	27,320	1,000,296	measured domains	2.73
2026-08	JZ8PY	tier_enforced	207,651	1,000,296	measured domains	20.76
2026-08	JZ8PY	tier_dead_of_valid_records	128,980	469,415	valid DMARC records	27.48
2026-08	JZ8PY	spf_record_published	639,844	1,000,296	measured domains	63.97
2026-08	JZ8PY	spf_permerror	36,735	639,844	published SPF records	5.74
2026-08	JZ8PY	spf_permerror_too_many_lookups	16,591	639,844	published SPF records	2.59
2026-08	JZ8PY	spf_multiple_records	10,474	639,844	published SPF records	1.64
2026-08	JZ8PY	mta_sts_published	9,520	1,000,296	measured domains	0.95
2026-08	JZ8PY	tls_rpt_published	11,442	1,000,296	measured domains	1.14
2026-08	JZ8PY	bimi_published	17,339	1,000,296	measured domains	1.73
2026-09	GQJJK	domains_scanned	1,000,767	1,000,767	domains scanned	100
2026-09	GQJJK	domains_measured	1,000,424	1,000,767	domains scanned	99.97
2026-09	GQJJK	dmarc_lookup_failed	343	1,000,767	domains scanned	0.03
2026-09	GQJJK	dmarc_record_published	477,782	1,000,424	measured domains	47.76
2026-09	GQJJK	dmarc_record_valid	472,655	1,000,424	measured domains	47.25
2026-09	GQJJK	policy_none	237,064	1,000,424	measured domains	23.7
2026-09	GQJJK	policy_quarantine	117,055	1,000,424	measured domains	11.7
2026-09	GQJJK	policy_reject	118,536	1,000,424	measured domains	11.85
2026-09	GQJJK	tier_none	522,642	1,000,424	measured domains	52.24
2026-09	GQJJK	tier_broken	5,127	1,000,424	measured domains	0.51
2026-09	GQJJK	tier_dead	131,008	1,000,424	measured domains	13.1
2026-09	GQJJK	tier_monitoring	106,056	1,000,424	measured domains	10.6
2026-09	GQJJK	tier_partial	27,237	1,000,424	measured domains	2.72
2026-09	GQJJK	tier_enforced	208,354	1,000,424	measured domains	20.83
2026-09	GQJJK	tier_dead_of_valid_records	131,008	472,655	valid DMARC records	27.72
2026-09	GQJJK	spf_record_published	641,215	1,000,424	measured domains	64.09
2026-09	GQJJK	spf_permerror	36,598	641,215	published SPF records	5.71
2026-09	GQJJK	spf_permerror_too_many_lookups	16,482	641,215	published SPF records	2.57
2026-09	GQJJK	spf_multiple_records	10,448	641,215	published SPF records	1.63
2026-09	GQJJK	mta_sts_published	9,563	1,000,424	measured domains	0.96
2026-09	GQJJK	tls_rpt_published	11,542	1,000,424	measured domains	1.15
2026-09	GQJJK	bimi_published	17,428	1,000,424	measured domains	1.74

DMARC Census

A monthly DNS measurement of DMARC and SPF across the Tranco top 1 million domains, plus a cohort of US federal domains. Each edition is one scan. This repository holds the aggregate results of every edition.

The report for each edition, with its methodology, is at https://domaincanary.com/research/dmarc-census.

What we measured

We looked up the DMARC and SPF records of every domain on one pinned Tranco list, once a month. The September 2026 edition scanned 1,000,767 domains on 1 September 2026. 1,000,424 of them answered the DMARC lookup, and we call those the measured domains. 343 lookups failed after retries. Those domains could not be measured and we left them out. We never counted them as publishing no record.

In September 2026, 47.2% of measured domains published a valid DMARC record. 20.8% of measured domains published quarantine or reject with no pct or sp tag weakening it. 131,008 domains published p=none with no reporting address that could receive a report, which is 13.1% of measured domains and 27.7% of valid DMARC records.

Files

File	Contents
`headline.csv`	The headline counts for every edition, one row per metric. Each row has its count, its denominator and what the denominator is.
`<edition>/aggregates.json`	Every count and share published in that edition: adoption, policy, record quality, reporting addresses, SPF, mail providers and report vendors, by country, by TLD and for the US federal cohort.
`<edition>/manifest.json`	What you need to repeat the scan: the Tranco list id, the Public Suffix List hash, the resolvers, the scanner version and the scan times.
`SHA256SUMS`	Checksums of the data files.
`CITATION.cff`	How to cite the dataset.

The data is aggregate. It has counts and shares, and no record of how any single domain was configured.

Reading a share

A share in this dataset never stands alone. headline.csv gives the denominator for every row, because the same count is a different percentage of measured domains, of valid DMARC records and of published SPF records. Quote the share with its denominator and its edition.

One month of change is one data point. Draw a trend only across three or more editions.

Editions

Edition	Tranco list	Scan date	Domains scanned
2026-09	GQJJK	2026-09-01	1,000,767
2026-08	JZ8PY	2026-08-20	1,000,766

Source and citation

The population is the Tranco list: Victor Le Pochat, Tom Van Goethem, Samaneh Tajalizadehkhoob, Maciej Korczyński and Wouter Joosen, "Tranco: A Research-Oriented Top Sites Ranking Hardened Against Manipulation", NDSS 2019, https://doi.org/10.14722/ndss.2019.23386.

Editions from September 2026 are also archived on Zenodo. The series DOI is https://doi.org/10.5281/zenodo.22849900 and it resolves to the newest edition.

Suggested citation: Purvis, J. DMARC Census. DomainCanary. https://doi.org/10.5281/zenodo.22849900

License

CC BY 4.0. Reuse the data, including commercially, with attribution.

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