I am reviewing the settings for the mail sending service an application I'm working on uses (the service is a mailchimp acquisition called Mandrill).
I want to ascertain, when I send a test email to myself (at gmail.com) from this service, whether the traffic between mail servers uses TLS. I have access to the email that was sent to me (I have included headers below).
I plan to ask the vendor whether they support this feature, but I also wish to find out if I can verify what they tell me personally.
Delivered-To: email@example.com Received: by 10.79.123.142 with SMTP id k136xxxxxxxxxxxx; Tue, 5 Jul 2016 07:29:11 -0700 (PDT) X-Received: by 10.37.97.11 with SMTP id v11mxxxxxxxxxxxx.36.14nnnnnnnnnnn; Tue, 05 Jul 2016 07:29:11 -0700 (PDT) Return-Path: <firstname.lastname@example.org> Received: from mail180-123.mandrillapp.com (mail180-123.mandrillapp.com. [a.b.c.d]) by mx.google.com with ESMTPS id mmmmmmmmmmm.nnn.2016.07.05.07.29.11 for <email@example.com> (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 05 Jul 2016 07:29:11 -0700 (PDT) Received-SPF: pass (google.com: domain of firstname.lastname@example.org designates a.b.c.d as permitted sender) client-ip=a.b.c.d; Authentication-Results: mx.google.com; dkim=pass email@example.com; dkim=pass firstname.lastname@example.org; spf=pass (google.com: domain of email@example.com designates a.b.c.d as permitted sender) firstname.lastname@example.org; dmarc=fail (p=NONE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; s=mandrill; d=mail180-123.mandrillapp.com; h=From:Sender:Subject:Reply-To:To:Message-Id:Date:MIME-Version:Content-Type; email@example.com; bh=xxxxxxxxxxxxxxxxxxxxxxx+8fQ=; b=n+xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/xxxxxxxxxxxxxxxxxxxxxxxxxxxx+Z+tSJV/zEtr xxxxxxxxx+xxxxxx+xxxxxxxxxxxxxxxxxxxxxx/xxx/xxxxxxxxxxxxxxxx/xxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx= Received: from pmta03.mandrill.prod.suw01.rsglab.com (127.0.0.1) by mail180-123.mandrillapp.com id xxxxxxxxxxxx for <firstname.lastname@example.org>; Tue, 5 Jul 2016 14:29:11 +0000 (envelope-from <email@example.com>) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mandrillapp.com; firstname.lastname@example.org; q=dns/txt; s=mandrill; t=1467728951; h=From : Sender : Subject : Reply-To : To : Message-Id : Date : MIME-Version : Content-Type : From : Subject : Date : X-Mandrill-User : List-Unsubscribe; bh=xxxxxxxxxxxxxxxxxxxxxxxx+xxxxxxxxxxxxxxxxxx=; b=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx+xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxx= From: recipient <email@example.com> Sender: recipient <firstname.lastname@example.org> Subject: =?utf-8?Q?Subject Return-Path: <email@example.com> Received: from [208.nnn.nnn.nnn] by mandrillapp.com id xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx; Tue, 05 Jul 2016 14:29:11 +0000 Reply-To: <firstname.lastname@example.org> To: ClientSeq ClientMcD <email@example.com> Message-Id: <firstname.lastname@example.org> Date: Tue, 05 Jul 2016 14:29:11 +0000 MIME-Version: 1.0