Hi!
Message-ID is one of the very few _mandatory_ header lines, so a message
without one is not a valid RFC 5322 (the sucessor of RFC 822) message.
Therefore the message "must not/cannot" leave your computer without one.
It has to be set on the computer if it's being shipped by a mail-related
protocol ((E)SMTP/LMTP/IMAP/POP[23]/...).
What you _can_ do (if I remember my sendmail.cf right, it's been a few
years since I taught that course ... ;-) ) is to _modify_ the Message-ID
header in your mail server. "If it looks like it's coming from the
computer, then modify Message-ID to look like ... (bla)". But I wouldn't
recommend it. Message-ID is supposed to be set by the sending software
(the Mail User Agent (MUA)) and it's supposed to uniquely identify the
message across all messages in the world ... ever. Modifying it would
make it very difficult to trace and debug how the message traverses the
Internet (which includes your computer). You can probably also influence
exactly how Emacs generates the Message-ID, but again, it's probably not
a good idea to mess with that.
Can I ask what problem you see with having your Emacs generate the
Message-ID?
Best regards,
/Lars-Johan Liman
rameik...@posteo.net 2023-12-08 18:44 [+0000]:
> Hello everyone! I'm on Emacs 29.1 and I use Message and sendmail for
> writing emails. I don't load Gnus but I do the easy C-x m. I can't get
> Emacs not to add Message-ID to my outgoing mail! I would be very
> grateful if some of you could help me out a little, I'm kind of a
> beginner. I set https://bpa.st/QLDQ and yet every email I write
> contains a message-ID which is set by emacs, rather than my email
> server.
> If I customize message-user-fqdn then the Message-ID will reflect
> that. Therefore whatever is setting my message ID despite the config
> telling Message not to, is taking it from the variable
> message-user-fqdn!
> Help is very much appreciated!
