SPF Record Validator & Lookup Counter.
Validate authorized sending IPs and includes, test for duplicate records, and check your progress against the critical 10-lookup DNS limit.
What this validator analyzes:
An SPF record specifies who can send mail as your domain. Sortwell checks your syntax and prevents email delivery blocks:
include, a, and mx mechanisms.-all Hardfail vs ~all Softfail vs dangerous +all).The 10-DNS Lookup Rule Explained.
Under RFC 7208 Section 4.6.4, an SPF query that triggers more than 10 DNS queries automatically fails with a PermError. Learn how to stay within safe boundaries.
What mechanisms count toward the 10-lookup limit?
Any mechanism that requires a DNS resolution counts: include: (+1), a (+1), mx (+1), ptr (+1), exists (+1), and redirect= (+1). Direct IP mechanisms like ip4: and ip6: do not count toward the 10-lookup limit.
Can a domain have two SPF records?
No. Publishing more than one TXT record starting with v=spf1 is a violation of RFC 7208 §3.2. Receiving servers will immediately abort SPF evaluation and treat messages as failing SPF.
What is the difference between -all and ~all?
-all (Hardfail) tells mailbox providers to reject unauthorized mail outright. ~all (Softfail) marks unauthorized mail as suspicious, usually delivering it to the spam/junk folder.
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