Make Postfix Trigger Blacklistd on Failed Authentication

The other day, I realized that from time to time, alpine, my console mail client for about 20+ years now, would close the connection to the IMAP server because of an “error”. Digging in the logs, I realized my server was being bruteforced for months, if not years. NetBSD being the fantastic OS it is, it actually had nearly no effect on my server’s behaviour, only those annoying connections closing from time to time.