Powermta Configuration Guide Top [extra Quality] -

ISPs will rate-limit or block your IPs if you open too many connections or send too many emails per hour. You must configure custom rules for each major provider.

You must tell the internet who you are. Failing to set these results in poor reputation scores. powermta configuration guide top

<dkim mydkim> sign yes selector pmta2024 domain senderdomain.com key-file /etc/pmta/dkim/private.key canonicalization relaxed/simple sign-headers From:Date:Subject:To:Message-ID </dkim> ISPs will rate-limit or block your IPs if