Unknown message in Sent folder

While looking in my sent folder of my MIAB server I noticed an email message that I never sent. It clearly looks like SPAM and I am very keen to figure out where it came from. The message headers do not look like it went through my mail system and the from/to appear to be from me:

From: Chris chris@dscoduc.com
X-Pgp-Agent: GPGMail 2.6b2
Content-Type: multipart/signed;
protocol=“application/pgp-signature”; micalg=pgp-sha512
X-Smtp-Server: ECBBFB7E-6F8B-4B18-B12F-65098689AAED
Subject: Fwd: Trust me, this will cure your DIABETES!
Date: Thu, 21 Apr 2016 13:44:16 -0700
X-Universally-Unique-Identifier: ABD4CB32-FF97-4E82-8A16-E980F66EA76E
References: 20160422043224.1F901A83821C1B7C@dscoduc.com
To: chris@dscoland.com
Message-ID: B350D018-E984-4A27-8F24-A9273AA4771F@dscoduc.com
MIME-Version: 1.0

Content-Transfer-Encoding: 7bit
Content-Type: text/plain;

Looking at the header information it clearly came from my Mac mail client since I have PGP configured to attach a signature with all outgoing email… I also don’t recognize the server header

X-Smtp-Server: ECBBFB7E-6F8B-4B18-B12F-65098689AAED

Looking at the output from mxtoolbox.com it seems I am not an open relay:

Connecting to
220 box.epiphyte.xyz ESMTP Postfix (Ubuntu) [1939 ms]
EHLO PWS3.mxtoolbox.com
250-SIZE 134217728
250 DSN [609 ms]
MAIL FROM:supertool@mxtoolbox.com
250 2.1.0 Ok [672 ms]
RCPT TO:test@example.com
554 5.7.1 test@example.com: Relay access denied [828 ms]

Does anyone know what’s going on here?

You could try looking at /var/log/mail.log to see if this message was actually sent, what IP address submitted it, and where it went.

I searched the mail.log for a matching “Message-ID:” value but came up empty… Any other place to look?

The message ID may not be in the log.