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Technical analysis

SPF record analyser

Parse an SPF record, count its DNS lookups, and find what will break it.

Short answer

An SPF record is valid when it starts with v=spf1, appears exactly once on the domain, resolves within ten DNS lookups including everything its includes pull in, and ends with -all or ~all. The lookup limit is what breaks most records: exceeding it returns permerror, which receivers treat as having no SPF at all.

Read it from DNS with dig +short TXT example.com, then paste the value here. Quoted, multi-string records are joined the way a resolver joins them.

Runs entirely in your browser. The record you paste is never sent to a server, logged, or stored — this page has no backend to send it to.

Paste a record to see the findings. Nothing is checked until you do.

How to use it

  1. Read the record from DNS: dig +short TXT example.com and take the string starting with v=spf1.
  2. Paste it into the analyser and read the findings top down; errors break authentication, warnings are hardening.
  3. Fix the lookup count first if it is flagged — a permerror disables SPF for every message.
  4. Re-query DNS after publishing changes and paste the new value to confirm.

Frequently asked questions

Does this tool query DNS for me?

No. It analyses the record you paste, so nothing you enter leaves your browser. Fetch the record with dig or your DNS provider's console first.

How accurate is the lookup count?

Terms in the record are counted exactly. Nested includes are counted using the published cost of well-known vendors; an unrecognised include is counted as one, so the real total may be higher. Treat the number as a floor.

Is ~all or -all correct?

Use ~all while you are still finding sending sources in DMARC reports, then move to -all once every legitimate source passes.

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