Fetchmail connects to your provider's e-mail server as if it were an MUA, then feeds mail to your server's MTA as if it were a peer MTA. If your provider doesn't allow client connections (by IMAP or POP), then you're right that fetchmail won't help.
It sounds as though you need to set up some kind of failover for your MTA: a second SMTP server, probably configured to feed your primary SMTP server (which then feeds mails to dovecot), but with a very long queue and many retry attempts. Then set your Internet-facing router to direct SMTP connections to your primary SMTP server (if it's up), falling back to your secondary server if the primary is down.
That's not really a dovecot problem: dovecot replication solves the problem "I cannot read my e-mail when my IMAP server is down" [1], and I think the problem you want to solve is "My provider throws away e-mail when my SMTP server is down"?
[1] And load management, and backup, and probably other stuff, none of which is relevant here.
Nick
On 04/06/2020 06:13, Andrea Miconi wrote:
I read about fetchmail. I understand that it doesn't work if the mail server uses an MTA.
Il mercoledì 3 giugno 2020, 15:07:51 CEST, Nicholas Taylor <net20@cam.ac.uk> ha scritto:
This is pretty much exactly what I do. I use fetchmail [1] to download mail from my ISP and feed it to exim, which delivers everything to dovecot. I don't know whether it's possible to configure dovecot alone for this.
[1] It's horrible, but it worked in 2007 and I'm intensely lazy.
Nick