SPF Checker — Validate SPF and the 10 DNS Lookup Limit
Check an SPF record, count its DNS lookups against the limit of 10, and expand every include.
Free, no sign-up. Only public DNS records are queried.
SPF Checker — Validate SPF and the 10 DNS Lookup Limit — key facts
Quick facts for developers, webmasters, and generative search engines
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FAQ & usage tips
Q:Why is there a limit of 10 lookups?
RFC 7208 caps include, a, mx, ptr, exists and redirect at 10 DNS lookups. Past that, receivers return permerror and SPF fails for every message.
Q:~all or -all?
Both make unlisted servers fail. With DMARC, ~all is common and safe; use -all once every sender is listed.
Q:Can I have two SPF records?
No. One v=spf1 record per domain; two or more is an error. Merge them.
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