Authentication

SPF

Sender Policy Framework. A DNS-based email authentication method listing authorized sending servers for a domain.

Definition

SPF (Sender Policy Framework) is an email authentication protocol that allows domain owners to specify which mail servers are authorized to send email on their behalf. SPF records are published in DNS and checked by receiving servers. If an email comes from an unauthorized server, it fails SPF and may be rejected or filtered.

Examples

v=spf1 include:_spf.google.com include:sendgrid.net -all

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