Email · Website glossary

SPF

Quick answer · What is SPF?

Sender Policy Framework lets a domain publish which senders are authorized for the envelope-from or HELO identity used in mail transport.

IN PRACTICE

SPF: an example

A business includes its legitimate sending service in its domain's SPF policy.

KEEP IN MIND

SPF does not directly authenticate the visible From address; DMARC alignment relates authenticated domains to that identity.

Put the idea to work

Frequently asked questions

What is a practical example of SPF?

A business includes its legitimate sending service in its domain's SPF policy.

Does SPF directly authenticate the visible From address?

SPF does not directly authenticate the visible From address; DMARC alignment relates authenticated domains to that identity.

Which concepts should I read alongside SPF?

DKIM: DomainKeys Identified Mail attaches a domain-associated cryptographic signature that receiving systems can verify using DNS.
DMARC: An email authentication policy and reporting mechanism that relates SPF or DKIM authentication to the visible From domain through alignment.