Check DMARC records for email security. Build policies with reject/quarantine/none, reporting URIs, and alignment modes.
Inspect an existing DMARC record or assemble one from policy, reporting, and identifier-alignment choices. The checker interprets the semicolon-separated tags in a DMARC TXT value and identifies whether its required version and policy structure are usable. The builder formats the selected settings as a record suitable for DNS publication. A common surprise is that p=none still performs DMARC evaluation and can request aggregate reports; it asks receivers to take no policy-based enforcement action.
Enter the TXT value beginning with v=DMARC1. The checker evaluates its tag-value structure, including the required policy tag and recognized settings for aggregate reporting and SPF or DKIM alignment. Policy values describe the requested treatment of failing mail: none, quarantine, or reject. A successful syntax check concerns the entered value, not its presence in public DNS.
Choose a policy and optionally supply reporting URIs and alignment modes. The builder combines those choices into a semicolon-separated DMARC value for the TXT record at _dmarc followed by the domain name. The adkim and aspf tags select relaxed or strict identifier alignment. Building the value does not publish it or configure the domain's SPF and DKIM records.
No. DMARC passes when at least one supported authentication path passes and aligns with the domain in the visible From field: aligned DKIM or aligned SPF. The checker can assess the record's declared policy and settings, but it cannot establish how a particular message was signed, routed, authenticated, or evaluated by a receiver.
Strict alignment requires the relevant authenticated domain to match the From domain exactly. Relaxed alignment permits domains that share the same organizational domain under DMARC's domain comparison rules. The adkim tag controls DKIM alignment, while aspf controls SPF alignment. Strict mode can expose legitimate mail streams that use related but nonidentical domains.
The behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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