The configuration above watches for specific Microsoft error responses (like 421 RP-001 or 421 4.3.2 System busy ). When detected, PowerMTA automatically shrinks your allowed connection footprint and hourly throughput for a designated cool-down period. Essential Best Practices Beyond the Configuration File
<domain *> max-smtp-out 20 queue-size 2000 max-message-size 10M use-remote-queue true </domain>
address bounce-handler@example.com reject-non-retryable false max-bounces-per-hour 100 sample powermta configuration file hot
# Rate and connection tuning max-smtp-out 20 # Maximum concurrent outbound connections per domain max-connect-rate 10/m # Max new connections per minute to a domain max-msg-per-connection 200 # Max messages per single SMTP connection max-msg-rate 5000/h # Max messages per hour per recipient domain max-cold-virtual-mta-msg 5000/day # Daily per-domain limit for cold IP warmup
for IP reputation management. AI responses may include mistakes. Learn more The configuration above watches for specific Microsoft error
source-ip 192.168.1.101 default-virtual-mta "vmta-pool-1" smtp-name mail1.yourdomain.com
A standard configuration consists of several core sections: global settings, listener settings, and Virtual MTA (VMTA) definitions. 1. Global and Network Settings AI responses may include mistakes
Before deploying this config, ensure:
; Local delivery for bounces and incoming domain-local
Below is a concise, production-ready example PowerMTA (PMTA) configuration focused on "hot" (high-throughput, reputation-conscious) email delivery. It includes global settings, listener(s), virtual MTAs, smart host routing, per-IP and per-domain throttling, bounce handling, and feedback loop/dkim/spf basics. Adjust names, IPs, domain, credentials, and limits for your environment.
The speed of sending in messages per hour (h) or minute (m).