Powermta Configuration Guide Top -

: Run pmtad --check-config before restarting the service to ensure no syntax errors disrupt live traffic. View real-time status : pmtacmd show status Monitor active queues : pmtacmd show top queues Force clear a specific queue : pmtacmd schedule * /gmail.com

PowerMTA (PMTA) by Port25 is the gold standard for high-volume email delivery. This guide covers the top configuration strategies to optimize your outbound mail server for speed, security, and a strong sender reputation. 1. Global Server Infrastructure Setup

The "secret sauce" of PowerMTA is Backoff mode. It prevents you from blasting ISPs who are temporarily rejecting your mail.

Send a test email to a tool like Mail-tester to verify SPF, DKIM, and DMARC alignments.

Which are you connecting to PowerMTA?

Ensure your IP addresses are not blacklisted and have Reverse DNS (rDNS) properly configured.

<domain *> max-smtp-out 100 max-msg-rate 100/s max-msg-per-connection 100 use-starttls if-supported initial-pts 60 </domain>

<fbl-handler> command "/usr/local/bin/pmta-fbl-handler.pl" smtp-port 25 accept-email fbl@yourdomain.com </fbl-handler>

smtp-service callout-cache-db /var/spool/pmta/callout.db smtp-service callout-cache-ttl 86400 smtp-service callout-verify yes powermta configuration guide top

Test from an outside network to ensure the server is not an open relay.

max-msg-attempts 6 # Typical: 6 attempts over 2-3 days.

A VirtualMTA (vMTA) maps a specific source IP address to a specific hostname. Splitting traffic across multiple vMTAs prevents a bad sending campaign on one IP from burning your entire pool. Setting Up a VirtualMTA Group

You should never send marketing, transactional, and critical alerts from the same VMTA. Use to split traffic. : Run pmtad --check-config before restarting the service

: Keep configurations "lean" by using parameter inheritance. Move common settings to a shared source (e.g., source ) to reduce redundancy. Rate Limiting max-smtp-out to control connections. A setting of

To ensure this configuration matches your specific deployment environment, let me know:

Create a 2048-bit RSA private and public key pair. Place the private key in /etc/pmta/dkim/ .