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Old 24 Oct 2017, 09:54 AM   #1
aussieboykie
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Join Date: Dec 2002
Location: Sydney, Australia
Posts: 458
dmarc=fail with p=none;has-list-id=yes

I have changed the sender and receiver domain names in the following extract from the full header of a message that failed dmarc / alignment. The sender is legitimate and I have an address book entry for *@somedomain.com so I expected this mail to get through.

Is the failure due to has-list-id=yes and is there anything I can do or does the sender need to do something to fix this?

Regards, AB

Authentication-Results: mx4.messagingengine.com;
arc=none (no signatures found);
dkim=fail (bad RSA signature; 1024-bit rsa key sha256) header.d=somedomain.com header.i=hello@somedomain.com header.b=S0TasWhu;
dmarc=fail (p=none;has-list-id=yes) header.from=somedomain.com;
iprev=pass policy.iprev=148.105.13.161 (mail161.sea51.mcsv.net);
spf=pass smtp.mailfrom=bounce-mc.us4_7971961.544013-myname=mydomain.com@mail161.sea51.mcsv.net smtp.helo=mail161.sea51.mcsv.net;
x-aligned-from=fail;
x-ptr=pass x-ptr-helo=mail161.sea51.mcsv.net x-ptr-lookup=mail161.sea51.mcsv.net;
x-return-mx=pass smtp.domain=mail161.sea51.mcsv.net smtp.result=pass smtp_org.domain=mcsv.net smtp_org.result=pass smtp_is_org_domain=no header.domain=somedomain.com header.result=pass header_is_org_domain=yes
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Old 25 Oct 2017, 09:17 AM   #2
Terry
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Join Date: Jul 2002
Location: VK4
Posts: 2,514
I just did a search and their IP address is black listed by one company.

Have a look here and do a few searches. http://whatismyipaddress.com/ip-look...FYGbvAodAxMJEg
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Old 26 Oct 2017, 02:05 PM   #3
n5bb
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Join Date: May 2004
Location: Irving, Texas
Posts: 8,240
Fastmail has recently added many additional headers and I'm not sure how to interpret all of them. I would worry most about the DKIM failure. Was the message forwarded, or sent directly from the originating system to Fastmail?

Bill
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Old 26 Oct 2017, 02:30 PM   #4
aussieboykie
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Join Date: Dec 2002
Location: Sydney, Australia
Posts: 458
The message was sent directly to a list. The sender's credentials are in my address book.

List-Id:
560bd9fceddef9c231fda92aemc list <560bd9fceddef9c231fda92ae.150013.list-id.mcsv.net>
x-spam-known-sender:
no ("Email failed DMARC policy for domain"); in-addressbook
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Old 26 Oct 2017, 10:01 PM   #5
lane
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Join Date: Dec 2005
Location: Kars, NB, Canada
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Quote:
Originally Posted by aussieboykie View Post
The message was sent directly to a list. The sender's credentials are in my address book.

List-Id:
560bd9fceddef9c231fda92aemc list <560bd9fceddef9c231fda92ae.150013.list-id.mcsv.net>
x-spam-known-sender:
no ("Email failed DMARC policy for domain"); in-addressbook
So the path seems to me to be the following:
sender with credentials => mailing list => you at Fastmail

The forwarding by the mailing list would break spf for the original sender, but Fastmail does not even check that. Fastmail would only check spf for the envelope sender, which is the mailing list. This succeeded, but does not align with the original sender (the "From:" field), which the mailing list must have left unchanged. And then the mailing list changed the message slightly so the sender's DKIM signing would fail. Because both spf failed (it wasn't the original sender that verified OK) and DKIM as well, then DMARC failed.

I'm not sure what Fastmail currently does if the original sender has p=reject or p=quarantine. But your question seems to be specifically, why does Fastmail not allow the message given the credentials in your address book. It is because all the checks that the message really came from that sender failed. Note, of course, it did not come from that sender specifically, it came from a mailing list to which the sender had submitted the message, and the mailing list changed the message slightly.

Have I got it right? Reference: https://en.wikipedia.org/wiki/DMARC#Mailing_lists
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Old 27 Oct 2017, 10:40 AM   #6
aussieboykie
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Location: Sydney, Australia
Posts: 458
Quote:
Originally Posted by lane View Post
..and the mailing list changed the message slightly.
Thanks. Your detailed analysis coincides with my interpretation of what is happening. The email itself is innocuous - a marketing mail shot from a reputable company. There is no obvious change but of course as a recipient I have no way of knowing what changes might have been made.

Regards, AB
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