The tools

Which one do you need?

Check a record

Start with the combined checker. Enter your domain once to look up your SPF, DKIM and DMARC records together. You set your policy for mail that fails in your DMARC record. If you include a reporting address in the rua tag, receivers send reports to that address showing who sends mail as your domain.

If a bounce mentions SPF, run the SPF checker. The usual cause is a record that needs more than 10 DNS lookups. For a bounce that mentions DKIM, copy the selector from the DKIM-Signature: header of a message you sent, and look it up in the DKIM checker.

The checkers only read public DNS, so running one changes nothing on your domain. Mail servers read the same records when your mail arrives.

Run the email health check to see your records, your mail servers and whether they're on the SpamCop blocklist in one report, with the worst problem first.

Read a report or a message's headers

Use the report analyzer when a report has already arrived. Paste the aggregate report XML a receiver mailed you, or upload the file, and you'll see which of your senders passed. We don't store the file.

Use the email header analyzer when one message failed or went to spam. Paste its headers and you'll see the SPF, DKIM and DMARC results the receiving server recorded, and the domain each check was for. You can share most results by link. The link holds only the summary, so we make none for a result that names a mail server.

Write a record

Give either generator your domain and we start from the record you publish today, so you don't lose a sender you forgot to list. With the SPF record generator, we add your senders in front of the all at the end and warn you if the new record goes over the lookup limit. With the DMARC record generator, we change the policy and add your reporting address, and leave every other tag as it was.

Change a record

Run the SPF change pre-flight before you publish an edit. Give it your domain and the new record. You'll see which address ranges would stop passing SPF, the include each one came from, and the new lookup count.