Thank you everyone for the interest shown so far. I appreciate the suggestions about Packet Capture (sure, Wireshark can use a certificate for decryption), DKIM (interesting, but overcome by events -- see below), etc.
The kind of answer I was expecting was along the lines of "Obviously your data has been mis-interpreted as XYZZY encoding. You can read about XYZZY encoding here <link to RFC/Wikipedia/whatever>." (I did not say so, not wanting to launch preconceptions.) My investigation has continued with the kind help of other mail users at my location, and it has become clear that Outlook 2007 or mutt 1.10 (Debian 10) correctly presents the data; later versions of Outlook (2016 or later) do not. The first line of the key is always changed in the same way. For the benefit of those following along at home, the path is: Outlook 2007 => exim4 => /var/mail/<username> => dovecot => Outlook 2016/2019/365 (corrupt) Outlook 2007 => exim4 => /var/mail/<username> => mutt (OK) Outlook 2007 => exim4 => /var/mail/<username> => dovecot => Outlook 2007 (OK) Unless someone knows about 'XYZZY encoding', it is probably time to call this as resolved as it can be. I have cautioned my users about sending data to be used by programs as plain text email. Changing the email client is way outside my pay grade. Thanks again, Ken -----Original Message----- From: mailop [mailto:[email protected]] On Behalf Of Ken Johnson via mailop Sent: Thursday, September 02, 2021 12:58 PM To: [email protected] Subject: [mailop] Corrupt plain text email I recently needed to send a software key to a remote colleague who needed to reinstall some commercial software after re-installing Windows. However, after the key failed to authorize, an investigation determined that the key was corrupt in the email he received from me. The first line of the key was truncated and repeated. This message only passes through the company email server, so the problem is limited in scope. (I have transmitted the key in another way in the meantime.) The key is 6 lines of plain text, visible non-blank ascii characters only. The first line of the key is: PXP70-KK4tQ6fJQYAI32PugLL4GK9pJOZT4ocM9J0ICAoharwSAYhplSMpFm+n+b2xJ65hNI043 which becomes: PXP70-KK4tQ6fJQYAI32PugLL4GK9pJOZT4ocM9J0ICAoharwSAYhplSMpFm+n+b2xJ65hNI PXP70-KK4tQ6fJQYAI32PugLL4GK9pJOZT4ocM9J0ICAoharwSAYhplSMpFm+n+043 by the time it is delivered to my remote colleague. This is repeatable, and this symptom also occurs if I send this key to another colleague working in the same remote location. It does not occur if I send this key to myself. We are using different email clients. If the cause of this problem is obvious but overlooked by me, please let me know. Thanks. Ken _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
