What is a DNS DMARC record?

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Every place a page here uses this source, in the order the words come in it.

1. What is a DMARC report? “DMARC reports are extremely important because they give administrators the information they need to decide how to adjust their DMARC policies — for instance, if their legitimate emails are failing SPF and DKIM, or if a spammer is trying to send illegitimate emails.” The example.com administrator would add the rua part of this policy to send their DMARC reports to a third-party service (with an email address of "[email protected]"):

   In DMARC reporting

2. What is a DMARC policy? “An email either passes or fails SPF and DKIM.” Example.com's domain policy could be:

   In Email authentication testing