Definition
Email domain authentication is a set of DNS-based standards that prove your mail genuinely comes from your domain and was not spoofed. The three core protocols are SPF, DKIM and DMARC.
SPF declares which servers may send for your domain; DKIM cryptographically signs messages; DMARC formalizes alignment and tells receiving providers what to do when authentication fails, plus provides reporting.
To authenticate well: publish and maintain SPF, generate a valid DKIM signature, then apply a DMARC policy with reporting, moving toward stricter enforcement as you gain confidence. Alignment of the domain is the key to DMARC working.
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Related Glossary Terms
Email Authentication Protocols
Email authentication protocols are technical standards that verify the identity of an email sender, helping mailbox providers distinguish legitimate mail from spam and phishing.
DMARC Alignment
DMARC identifier alignment determines whether the domain in the From header matches the domains used in SPF and DKIM authentication. Strict or relaxed.
DMARC Policy Tags
DMARC DNS record tags including v, p, sp, rua, ruf, pct, adkim, aspf, fo, rf, and ri control authentication policy, reporting, and alignment enforcement.
Email Authentication Guide
Email authentication is proving an email's legitimacy to mailbox providers using standards like SPF, DKIM and DMARC, which protect your domain and improve deliverability.
DMARC Policy Graduation
DMARC policy graduation process from p=none through p=quarantine to p=reject, including subdomain staging, false positive handling, and typical timelines.
Email DMARC Reporting
DMARC reporting provides aggregate and forensic reports showing how receiving ISPs handle email authentication for your domain, including pass/fail rates and source IP breakdowns.
Frequently Asked Questions
It is DNS-based standards (SPF, DKIM, DMARC) that prove an email genuinely comes from your domain, preventing spoofing and improving deliverability.
DMARC alignment checks that the domain in the From header matches what SPF and DKIM authenticated, which makes the policy effective.
Publish SPF, set up DKIM signing, then roll out DMARC with monitoring before enforcing, and keep all records consistent with your sending infrastructure.