# Fallback for subdomains dkim-signer * dkim-default /etc/pmta/dkim/default.key </domain> To track which recipient bounced, use Variable Envelope Return Path (VERP).
<domain gmail.com> max-smtp-out 20 # Concurrent connections max-message-rate 1000/h # Messages per hour per VMTA vmta "marketing" <limit> max-data-errors 5 </limit> </domain> <domain outlook.com> max-smtp-out 15 max-message-rate 800/h vmta "marketing" </domain> For new IPs, create a dedicated VMTA that sends only 100 messages then pauses. powermta configuration guide top
pmta flush domain gmail.com There is no "set and forget" config for PowerMTA. The top senders in the world treat their pmta.conf as a living strategy. As ISPs like Gmail and Yahoo roll out new anti-spam measures (like requiring one-click unsubscribe and strict DMARC), your PowerMTA must evolve. The top senders in the world treat their pmta
Disclaimer: PowerMTA is a licensed software. This guide assumes you have a valid license from SparkPost/Port25. This guide assumes you have a valid license
queue-mem-pool-size 2048M large-message-threshold 262144 # 256KB Assign specific CPU cores to specific domains to prevent cross-domain blocking.
# Allow only authenticated or specific subnets access-source blocklist /etc/pmta/blocklist.txt <source *> # Deny all by default allow-relay no </source>
<processor-set name="high_volume"> cpu-range 0-3 <domain gmail.com> assign-processor-set high_volume </domain> </processor-set> <processor-set name="low_volume"> cpu-range 4-7 <domain *> assign-processor-set low_volume </domain> </processor-set> Many ISPs greylist unknown senders. PowerMTA can auto-retry with smarts.