Glossary term
Email authentication (SPF, DKIM, DMARC)
Also called: SPF DKIM DMARC
Email authentication is a set of DNS records that prove your mail is legitimate. SPF lists servers allowed to send for your domain, DKIM signs each message, and DMARC tells receivers what to do when checks fail.
Why all three
SPF and DKIM verify the sender; DMARC ties them together and sets a policy. Missing or misconfigured records are a common reason cold email lands in spam.
A 2026 baseline
Major mailbox providers now require proper authentication for bulk senders. It is table stakes, not an optimization, before any cold campaign.
See how email authentication (spf, dkim, dmarc) works in a real outbound system.
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