Thanks for your valuable input, everyone, and lane and Bill in particular. It's much appreciated.
I've managed to find a message that was delivered to my wife's Fastmail account, but never made it to Gmail. These are the full headers:
Code:
Return-Path: <international@emarsys.net>
Received: from compute2.internal (compute2.nyi.mail.srv.osa [10.202.2.42])
by sloti19t10 (Cyrus git2.5+0-git-fastmail-9538) with LMTPA;
Sun, 15 Dec 2013 02:26:11 -0500
X-Sieve: CMU Sieve 2.4
X-Spam-score: 1.6
X-Spam-hits: BAYES_50 0.8, HTML_IMAGE_RATIO_04 0.556, HTML_MESSAGE 0.001,
MIME_HTML_ONLY 0.723, RP_MATCHES_RCVD -0.435, T_FRT_CONTACT 0.01,
T_KHOP_FOREIGN_CLICK 0.01, LANGUAGES da, BAYES_USED global,
SA_VERSION 3.3.2
X-Spam-source: IP='91.211.240.12', Host='pmta40012.emarsys.net', Country='AT',
FromHeader='dk', MailFrom='net'
X-Spam-charsets: subject='UTF-8', html='utf-8'
X-Resolved-to: mywife@fastmail.fm
X-Delivered-to: mywife@ourdomain.com
X-Mail-from: international@emarsys.net
Received: from mx4 ([10.202.2.203])
by compute2.internal (LMTPProxy); Sun, 15 Dec 2013 02:26:11 -0500
Received: from pmta40012.emarsys.net (pmta40012.emarsys.net [91.211.240.12])
by mx4.messagingengine.com (Postfix) with ESMTP id 109B13C00AA
for <mywife@ourdomain.com>; Sun, 15 Dec 2013 02:26:11 -0500 (EST)
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; s=key2; d=nyheder.bilka.dk;
h=To:Subject:From:MIME-Version:List-Id:List-Unsubscribe:Content-Type:Content-transfer-encoding:Message-ID:Date; i=mail@nyheder.bilka.dk;
bh=8dcOBdySHD1kR+eDzgs2xKB0cJ0=;
b=DBaPWAZBXbvm0ZlqLvk90uTQnPUWEJvMjQhM6SFGj8qChJDzqysMeeBNJX0Rs31mNA4ngnBDKcJ1
w9jvP1f6p3eFSHCmKRb0fNO9EUoAzIwzz26v5OJHJJI1ZZRcRV+Pttk9eatdY7/+D3nBLdwMIW3n
oCjvtd/6Z+XfsRpfDbc=
DomainKey-Signature: a=rsa-sha1; c=nofws; q=dns; s=key2; d=nyheder.bilka.dk;
b=g8UxAeLzF5G4ym07fWoM5rN4Q/075P4/yvb5QCK9CCg2h0rfdElJyFl73HINwB1wkuG5M7MsYGH1
97/IEsOxIQcbTT3zVQUaElwW8SIWrA04815BNvcVO1EKZRayS9qb6PBhmcMnhHU8Opy8pVwoNZwX
tSWfnkT7OGN8DzyqYi4=;
Received: from (91.194.249.233) by pmta40012.emarsys.net id hllcp616nd8n for <mywife@ourdomain.com>; Sun, 15 Dec 2013 08:26:09 +0100 (envelope-from <international@emarsys.net>)
To: <mywife@ourdomain.com>
Subject:
Det Store Gaveguide | Shop julegaver til hele familien i dag | Dagens
JuleNetkup | Inspiration til gaverne til ham, hende,
=?UTF-8?Q?b=C3=B8rnene=20og=20teenageren?=
X-Mailer: class SMTPMail
From: "Bilkas netbutik" <mail@nyheder.bilka.dk>
MIME-Version: 1.0
X-EMarSys-Identify: 121595857_758214_94641
List-Id: 121595857 <Bilkas netbutik>
X-EMarSys-Environment: international
X-CSA-Complaints: whitelist-complaints@eco.de
List-Unsubscribe: <http://link.bilka.dk/u/lu.php?lu=nbsaA:xBPF:,pW:nJ5qDH2n3z>
Content-Type: text/html; charset=utf-8
Content-transfer-encoding: quoted-printable
Message-ID: <0.1.47.935.1CEF966ECBAC760.0@pmta40012.emarsys.net>
Date: Sun, 15 Dec 2013 08:26:09 +0100
As I understand from lane, DMARC looks at the domain in the From: header, which in this case is "nyheder.bilka.dk". This (sub)domain does indeed have a published DMARC record with instructions to reject invalid messages (p=reject), as you can see here:
https://dmarcian.com/dmarc-inspector/nyheder.bilka.dk
However, pasting the message into an online DKIM validator (e.g.,
https://9vx.org/~dho/dkim_validate.php), it looks like the signature checks out.
Since forwarding from FM doesn't modify the DKIM signature, it should also check out at Gmail's end.
I'm unable to tell if the sender of this particular message received a bounce or not. They may have, or they may not.
Any thoughts?