In a standard Linux installation (such as CentOS or Ubuntu), the primary configuration file is located at: /etc/pmta/config
domain yourdomain.com selector default private-key-file /etc/pmta/dkim/private.key Use code with caution. Best Practices for Management Smart Email Verifier PowerMTA: Guide to High-Deliverability Email in 2025 powermta config file link
Crucial for maintaining IP reputation by preventing "blasting" that triggers ISP spam filters. max-msg-rate : Limits messages per minute or hour. In a standard Linux installation (such as CentOS