Sender Policy Framework (SPF)

Sender Policy Framework (SPF) lets a domain publish which sending systems are authorized for its email envelope domain.

Format
Email & Communication
Updated
Updated
Glossary Email & Communication
Sender Policy Framework Also known as SPF.Aliases: SPF record, email sender policy.

Definition

Sender Policy Framework (SPF) lets a domain publish which sending systems are authorized for its email envelope domain.

How it works

The policy lives in a TXT record and lists the servers allowed to use your domain in the SMTP envelope. Receivers check the connecting IP against that list. It is a solid first layer with a known blind spot: forwarding often breaks it, because the forwarder's server is not on your list — one of the reasons DKIM and DMARC exist.

Example: A domain authorizes its chosen mail provider's servers while excluding everyone else.

Often confused: SPF authorizes sending servers; it says nothing about the message content, which is DKIM's territory.

Sources

Last reviewed 2026-07-19.