SPF lists which servers may send mail for your domain. DKIM adds a cryptographic signature that proves a message wasn’t forged or altered. DMARC ties SPF and DKIM to the visible From address, tells receivers what to do when they fail, and sends you reports. You need all three: SPF and DKIM authenticate, DMARC enforces.
SPF is a DNS list of authorized sending servers. The receiver checks whether the server that delivered the message is on the list. Its weakness: it validates the hidden envelope sender, not the From address a human sees, and it breaks when mail is forwarded.
DKIM signs each message with a private key; the receiver verifies it with the public key in your DNS. It proves the message really came from your domain and wasn’t modified — and, unlike SPF, it survives forwarding.
DMARC requires that SPF or DKIM not only pass but align with the From domain, then applies your policy (none, quarantine, reject) and emails you reports. It is the only one of the three that actually stops someone spoofing your exact domain.
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Open the free Domain checker →Yes. SPF and DKIM each authenticate part of the picture; DMARC ties them to your From domain and enforces a policy. The Google/Yahoo 2024 rules require DMARC for bulk senders.
DKIM, because it aligns to your domain and survives forwarding. SPF alignment often breaks in real-world routing.
