On 12-10-2020 19:16, Robert Martin wrote:
I created a client library to send emails for a webapp.
After connecting to the SMTP server with credential setup in CPANEL,
and then do NOT add Message-Id header, the DKIM signature 'h' record
created by dovecot/WHM is wrong, and a Message-ID (with a capital D)
header is added, invalidating the generated DKIM signature value.
This causes outlook, yahoo, gmail and other email recipients to add
'dkim:fail' to the message, and thus relegate it to junk or spam.
The work around is to add to the message a Message-Id with a little
'd' header. Then the SMTP server processes the email with the correct
generated DKIM, correct DKIM 'h' record and does not add a Message-ID
header.
My SMTP hosting providers that run the WHM/dovecot/CPANEL software are
refusing to raise this as a bug and have requested that I do it.
Hardly a bug imo. Best to add the Message-Id header from your library
and this will become a non-issue. There are certain filters who don't
quite like emails without message-id header, or incorrectly formatting
ones because this is an usual fingerprint of a broken client / spam bot,
this is why your provider is adding that header.
--
Adi Pircalabu
