Why does SPF fail sometimes?

[Christian Rößner]

Hi,

sorry, if this question might be a little off-topic, but I really do not 
understand some DMARC reports that I receive in conjunction to this mailing 
list and maybe someone can help me in digging down the problem:

<?xml version="1.0" encoding="UTF-8" ?>
<feedback>
 <report_metadata>
  <org_name>*****.com</org_name>
  <email>noreply-dmarc@*****.com</email>
  <report_id>roessner-network-solutions.com:1418590509</report_id>
  <date_range>
   <begin>1418552542</begin>
   <end>1418552542</end>
  </date_range>
 </report_metadata>
 <policy_published>
  <domain>roessner-network-solutions.com</domain>
  <adkim>s</adkim>
  <aspf>r</aspf>
  <p>none</p>
  <sp>none</sp>
  <pct>100</pct>
 </policy_published>
 <record>
  <row>
   <source_ip>168.100.1.3</source_ip>
   <count>1</count>
   <policy_evaluated>
    <disposition>none</disposition>
    <dkim>pass</dkim>
    <spf>fail</spf>
   </policy_evaluated>
  </row>
  <identifiers>
   <header_from>roessner-network-solutions.com</header_from>
  </identifiers>
  <auth_results>
   <spf>
    <domain>postfix.org</domain>
    <result>unknown</result>
   </spf>
   <dkim>
    <domain>roessner-network-solutions.com</domain>
    <result>pass</result>
   </dkim>
  </auth_results>
 </record>
</feedback>

If I do understand this report right, DKIM passes, but SPF failed. If I look to 
my last mail, I sent this day, I see this in the headers:

DMARC-Filter: OpenDMARC Filter v1.3.0 mx.roessner-net.de 3k0hcj6S5RzGpN5
Authentication-Results: mx.roessner-net.de; dmarc=pass 
header.from=roessner-network-solutions.com
Authentication-Results: mx.roessner-net.de; spf=pass 
smtp.mailfrom=owner-postfix-us...@postfix.org
DKIM-Filter: OpenDKIM Filter v2.9.2 mx.roessner-net.de 3k0hcj6S5RzGpN5
Authentication-Results: mx.roessner-net.de;
        dkim=pass (2048-bit key; secure) 
header.d=roessner-network-solutions.com 
header.i=@roessner-network-solutions.com header.b=G+zYCJvI;
        dkim-adsp=pass; dkim-atps=neutral

So why does my own MX say, everything is fine, with incoming mails from the 
list, but I get reports from other people that SPF failed?

Is this a misconfiguration somewhere remote or am I missing something?

Thanks a lot for helping me

Kind regards

Christian
--
Bachelor of Science Informatik
Erlenwiese 14, 36304 Alsfeld
T: +49 6631 78823400, F: +49 6631 78823409, M: +49 171 9905345
USt-IdNr.: DE225643613, http://www.roessner-network-solutions.com

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