Juan Smitt Jr:
>
> Thank you for the explanation.
>
> Is it really risky to implement "always_add_missing_headers" if other headers
> (i.e. From) are present?
Yes. This would break DKIM signatures.
Wietse
> https://www.postfix.org/postconf.5.html#always_add_missing_headers
>
>
> Thanks!
>
>
>
>
>
> ------- Original Message -------
> On Friday, November 11th, 2022 at 13:17, Markus Sch?nhaber
> <[email protected]> wrote:
>
>
> > 11.11.22, 13:02 +0100, Juan Smitt Jr:
> >
> > > Can you help me please understand the "message-id" header?
> > >
> > > Sometimes it's missing from the emails and i.e. gmail rejects these
> > > emails.
> > >
> > > Is it added by the email client (application) or is it added by postfix?
> >
> >
> > The Message-ID header contains an unique identifier for the particular
> > message[1]. Every message should have one, and in general, especially
> > when real people communicate via e-mail, it's the sending MUA's (mail
> > client's) job to create one.
> > Depending on situation (for example when postfix itself creates a status
> > message) and configuration postfix might create a Message-ID, though.
> >
> >
> > [1]: https://datatracker.ietf.org/doc/html/rfc5322#section-3.6.4
> >
> >
> > --
> > Regards
> > mks
>
