Guides · Updated 2026-10-11

What is SPF? Sender Policy Framework explained

SPF (Sender Policy Framework) is a TXT record that lists which servers may send mail using your domain in the envelope sender (Return-Path). Receivers check the connecting server's IP against that list.

Example

v=spf1 include:_spf.google.com include:spf.protection.outlook.com -all

ip4: / ip6:: allow specific addresses (no DNS lookup needed).
include:: allow another domain's SPF list (costs at least one DNS lookup).
a, mx: allow your own A/MX hosts (each costs a lookup).
-all fail everything else; ~all softfail; ?all neutral; +all allows anyone and should never be used.

Rules that trip people up

Only one SPF record per domain. Two records is a permanent error. See fixing multiple SPF records.
Maximum 10 DNS-querying terms (include, a, mx, ptr, exists, redirect), counted recursively. Going over is a permanent error. See SPF too many lookups.
No more than 2 "void" lookups (lookups that return nothing) are allowed.

SPF and DMARC

SPF checks the envelope domain, not the From: header people see. For DMARC, SPF only counts when the envelope domain aligns with the From: domain. Many marketing platforms use their own envelope domain, so DKIM is usually what makes their mail pass DMARC.

Check your domain now. Our free checker grades DMARC, SPF, DKIM, MX, BIMI and MTA-STS in seconds.

Sources

This guide is general information, not legal or professional advice. Provider screens change; always confirm the exact values shown in your own account.