How can I check if my DKIM and SPF records are valid?

Postmark makes it very easy to authenticate your email messages with DKIM and SPF. If you have not already, login to Postmark and create a sender signature, then follow the steps.

If you are having trouble verifying your SPF or DKIM records there are two useful tools you can use. Keep in mind that DNS make take several hours to propagate.

Verify DKIM

Using DKIM Core Key Check tool, insert the text before the "._domainkey" as the selector (it looks something like this: 20130425164621.pm) and then your domain. If DKIM is valid, it should show a result of This is a valid DKIM key record. If the record is not valid, go back to the instructions in Postmark and check the details to make sure your DNS records match.

Verify SPF

Using SPF Record Testing tool, just insert your domain and click Get SPF Record. For Postmarkapp.com, it would show a result like this:

  <code>Checking to see if there is a valid SPF record.   Found v=spf1 record for postmarkapp.com:   v=spf1 a mx include:spf.mtasv.net include:_spf.google.com include:cmail1.com ~all

The important part to notice above is include:spf.mtasv.net which tells ISPs that Postmark can send on behalf of your domain.

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