FireEye...

[Rupert Gallagher]

...catched sending spam to a gmail address, twice, using our fqdn.

From google:

<?xml version="1.0" encoding="UTF-8" ?>

<feedback>

  <report_metadata>

    <org_name>google.com</org_name>

    <email>noreply-dmarc-supp...@google.com</email>

[...]

<policy_published>

    <domain>example.com</domain>

    <adkim>s</adkim>

    <aspf>s</aspf>

    <p>reject</p>

    <sp>reject</sp>

    <pct>100</pct>

  </policy_published>

  <record>

    <row>

      <source_ip>154.57.155.23</source_ip>

      <count>2</count>

      <policy_evaluated>

        <disposition>none</disposition>

        <dkim>pass</dkim>

        <spf>fail</spf>

      </policy_evaluated>

    </row>

[...]

From whois:

FireEye, Inc. FIREEYE-CGNT-154-57-155-1 (NET-154-57-155-0-1) 154.57.155.0 - 
154.57.155.255