max-smtp-out : Controls the maximum concurrent outbound SMTP connections globally. A value of 2000 enables heavy parallel processing required for "hot" lists.
A "hot" configuration file is useless if your IP is cold (new) or your lists are dirty.
dns-servers 198.51.100.1,198.51.100.2 dns-retry 30s
Without SPF, DKIM, and DMARC, a lifestyle brand looks like a counterfeit handbag. Entertainment emails must pass authentication with flying colors. sample powermta configuration file hot
In 2024 and beyond, DKIM isn't optional. Ensuring dkim-sign yes is active in your config ensures that every outgoing mail is cryptographically signed, which is a primary signal for "hot" deliverability to the inbox rather than the spam folder. Best Practices Before Going "Hot"
Opening an SMTP connection involves a "handshake" that consumes time and resources. By sending multiple messages (e.g., ) over a single connection, you significantly reduce the overhead per email. 3. Domain-Specific Throttling
This is crucial for throttling. It prevents you from sending too fast during a "hot" mailing spree. Finalizing Your Setup max-smtp-out : Controls the maximum concurrent outbound SMTP
Master Your Mail: A Sample PowerMTA Configuration File for High-Volume ("Hot") Mailing
# Logging log_level = 3 log_file = /var/log/powermta.log
; listeners (incoming/API) listener 25
<!-- Handling the Giants: Gmail --> <domain gmail.com> max-msg-rate 100/s <!-- Don't flood Google --> max-rcpt-per-transaction 100 <!-- Send in batches --> max-smtp-out 20 <!-- Max open connections --> retry-after 10m dkim-sign yes dkim-identity @yourdomain.com dkim-selector mail dkim-key-file /etc/pmta/dkim.key </domain>
Allows you to bind specific SMTP outgoing connections to specific IPs.
# Sample: /etc/pmta/config
The Ultimate Guide to a High-Volume PowerMTA Configuration File