Your goal does not sound weird.
OK, thanks for the confirmation.
The most painless way might be to fetch incoming messages from the ISP's IMAP and deliver them to your local dovecot. A shortened fetchmailrc would read:
poll remote.server … user …, password … folder 'INBOX' fetchall idle ssl mda "HOME=%T /usr/bin/sudo -u %T /usr/lib/dovecot/deliver"
Brilliant, thanks for the info.
That way your users can create their vacancies with the ISP portal, [...]
That's a good idea. But then internal e-mails need to go out to the ISP, don't they? Because, if internal e-mails get delivered locally, the vacation autoresponses on the ISP will not trigger, will they?
The trouble is, with that configuration, if the Internet link goes down, internal e-mail stops working too.
I was hoping that there would be a complete mail server setup guide somewhere for this kind of setup. But I guess I'll have to piece all these information snippets together.
Regards, rdiez