What is SPF?
Also called: Sender Policy Framework, SPF record
SPF, or Sender Policy Framework, is a DNS TXT record listing which mail servers may send email for a domain. A receiving server compares the sending server's IP with that list and treats a mismatch as a sign of forgery. It is one of the three records that make up modern email authentication.
The final qualifier says what to do with everything not listed: ~all is a soft fail, -all a hard fail, and +all authorises the whole internet and should never be used.
The most common mistake is going over the limit of ten DNS lookups set in RFC 7208. Each include:, a, mx and exists mechanism costs one, and exceeding ten makes the whole check return a permanent error rather than ignoring the extras.
SPF checks the envelope sender, not the From address a person sees. It only protects your visible brand when DMARC ties the two together. Google requires SPF or DKIM from every sender and both from bulk senders.
Example
v=spf1 include:_spf.google.com ip4:203.0.113.5 ~allGo deeper
Sources
By SimpleVerifier Team · Last reviewed 2026-10-13 · All 50 glossary terms