On 11/06/2020 16.26, Marc Roos wrote: > I know it is not dovecot who should fix this. But anyone using dovecot > is using an MTA, and receiving spam ;) I know how to look at email > headers. Spf and dkim is not solving anything here.
You can configure this sort of thing in postfix, exim etc. The part of the mail system to do with RECEIVING emails. Not really a dovecot function. Look at greylisting as an option. That's basically delaying email from unknown senders. Also blocklists Also consider setting up rules in spamassassin / rspamd
