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Ex Umbris
Asked: 2016-12-25 09:33:43 +0800 CST

DMARC configured to reject - I don't understand this report from Google

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I have DKIM and SPF configured, and set in my DMARC record for strict enforcement and policy=reject:

v=DMARC1; p=reject; adkim=s; aspf=s; fo=1; ri=3600; ...

Today I received the following DMARC report from Google

<?xml version="1.0" encoding="UTF-8" ?>
<feedback>
  <report_metadata>
    <org_name>google.com</org_name>
    <email>[email protected]</email>
    <extra_contact_info>https://support.google.com/a/answer/2466580</extra_contact_info>
    <report_id>13806158670451821840</report_id>
    <date_range>
      <begin>1482451200</begin>
      <end>1482537599</end>
    </date_range>
  </report_metadata>
  <policy_published>
    <domain>jhmg.net</domain>
    <adkim>s</adkim>
    <aspf>s</aspf>
    <p>reject</p>
    <sp>reject</sp>
    <pct>100</pct>
  </policy_published>
  <record>
    <row>
      <source_ip>209.17.115.53</source_ip>
      <count>1</count>
      <policy_evaluated>
        <disposition>none</disposition>
        <dkim>pass</dkim>
        <spf>fail</spf>
      </policy_evaluated>
    </row>
    <identifiers>
      <header_from>jhmg.net</header_from>
    </identifiers>
    <auth_results>
      <dkim>
        <domain>jhmg.net</domain>
        <result>pass</result>
        <selector>smtp</selector>
      </dkim>
      <spf>
        <domain>jhmg.net</domain>
        <result>fail</result>
      </spf>
    </auth_results>
  </record>
</feedback>

My interpretation of this is that the host at 209.17.115.53 (NOT my SMTP host) sent a DKIM-signed email to Google with a spoofed From: domain matching mine.

  <policy_evaluated>
    <disposition>none</disposition>
    <dkim>pass</dkim>
    <spf>fail</spf>
  </policy_evaluated>

How did the DKIM signature 'pass'? What does the <disposition>none</disposition> mean? Did Google not reject the email?

I was expecting that turning on strict enforcement would cause DKIM-verifying MTAs to reject spoofed email purporting to come from my domain.

google dkim dmarc

1 Answers

  1. <disposition>none</disposition> means Gmail applied "none" policy instead of "reject", and also as it accepts the dkim,the Most probably this happened because the message was forwarded to/ through that ip "209.17.115.53", check your logs if you sent message to that host,

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