SPF Checker & Lookup
Run a free SPF lookup to validate your domain's SPF record and improve email authentication.
SPF Checker FAQs
What is an SPF record?
SPF (Sender Policy Framework) is a DNS TXT record that lists the mail servers authorized to send email on behalf of your domain. Receiving servers check the SPF record to verify the sender is legitimate.
What does an SPF checker do?
An SPF checker retrieves your domain's SPF record from DNS, parses each mechanism, counts DNS lookups against the 10-lookup limit, and identifies security issues like missing -all enforcement or deprecated mechanisms.
What is the 10 DNS lookup limit?
RFC 7208 limits SPF evaluation to 10 DNS-querying mechanisms (include, a, mx, ptr, exists, redirect). Exceeding this limit causes a permanent error (PermError) and SPF effectively stops working for your domain.
What's the difference between ~all and -all?
-all (hardfail) tells receivers to reject emails from unauthorized servers. ~all (softfail) marks them as suspicious but still delivers them. Use -all for maximum protection once you've confirmed all legitimate senders are included.
How does SPF relate to DMARC?
DMARC uses SPF (and DKIM) to authenticate emails. For DMARC to pass via SPF, the domain in the envelope "From" must align with the SPF-authenticated domain. Check your DMARC record alongside SPF.
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