Here’s a solid, in-depth review of what a “sample PowerMTA configuration file” should look like — especially if you’re searching for a “hot” (high-performance, deliverability-focused) setup.

Throttling & Delivery Rules

<domain hotmail.com> max-smtp-out 10 max-msg-rate 20/s use-rs yes use-plaintext yes smtp-pipelining yes smtp-starttls required </domain>

5. DEFAULT DOMAIN DIRECTIVES

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This applies to domains not specifically defined above.

<domain *> max-msg-rate unlimited max-smtp-msg-rate 100/h max-connections 10 smtp-port 25

Check out the snippet below for the core /etc/pmta/config structure! ⬇️

2. Domain Throttling (The domain blocks)

The most common mistake is setting max-msg-rate unlimited. Major ISPs (Gmail, Outlook, Yahoo) will block you if you send too fast from a new IP.

• mailbox: defines a mailbox for the virtual domain