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Check a domain's SPF record

Paste a mail domain to read its SPF record and find the problems receivers trip over: no record, two records, a record that does not parse, or one that costs more than ten DNS lookups. It runs once with a 10 second cap, the same runner a monitor uses; the result says where it ran.

How to read this

SPF
The record as published, whether exactly one exists and parses, and how many DNS lookups evaluating it costs. More than ten and receivers stop reading it.
MX, DKIM and DMARC
The rest of the mail setup is read on the same run, so a missing DMARC policy shows up here too. Blocklists are left to their own page.

Questions

Why does the lookup count matter?

RFC 7208 caps SPF evaluation at ten DNS lookups. Every include, a, mx, ptr, exists and redirect counts; past ten, receivers return a permanent error and treat the record as failed.

Is this a scan?

No. It reads the domain's TXT, MX and DMARC records once, the way any receiving mail server does before accepting a message.

Related

Mail health monitoringThe records that keep mail deliverable, plus up to 8 sending addresses checked against the blocklists that actually get you rejected.

Read

SPF, DKIM and DMARC explained: how to read the records and the mistakes that get mail rejectedWhat SPF, DKIM and DMARC each do, how to read a record term by term, the dig commands, and the mistakes that get legitimate mail rejected.

Watch this for good.

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