Below is a complete example PowerMTA (PMTA) configuration file tuned for a "hot" sending setup — high throughput, multiple IPs, aggressive but controlled delivery, and common best-practice features (virtual MTA pools, bounce handling, authentication, rate controls, retry/backoff, logging). Adjust values (IP addresses, domains, paths, credentials, rate limits) to match your infrastructure, compliance needs, and recipient-reputation goals.
# Pool C: dedicated transactional IPs <pool name="txn"> ips 203.0.113.30 max-msg-rate 2000/hour max-conn-per-ip 100 concurrency 20 reputation-weight 1.0 </pool> Domain and smart host routing (example routing for gmail/yahoo/MSN with per-domain throttle) Rate shaping and per-connection handling default-remote-smtp-connection-rate 200/s default-remote-smtp-burst 10000 per-recipient-rate-limit 20/minute per-domain-message-rate 10000/hour Adaptive throttling & backoff adaptive-throttling yes min-backoff 30s max-backoff 24h backoff-scale-factor 1.5 Retry policy retry-intervals 10m,30m,1h,3h,6h,12h,24h max-delivery-attempts 10 soft-bounce-action delayed hard-bounce-action bounce Connection/timeout tuning smtp-timeout 60s connection-timeout 30s read-timeout 60s write-timeout 60s dns-timeout 10s DNS settings dns-servers 198.51.100.1,198.51.100.2 dns-retry 30s Greylisting / deferred handling greylist-enabled no Recipient verification / VRFY/EXPN handling allow-vrfy no allow-expn no Content filters (example integration points) content-filter smtp://127.0.0.1:10025 header-add X-Processed-By "PowerMTA hot-config" message-id-hostname mail1.example.com Suppression and global blocks suppress-file /etc/pmta/suppressions.list global-reject-file /etc/pmta/global_rejects.txt Per-sender policy examples (sending groups) <sender user@marketing.example.com> vmta hot-vmta max-msg-rate 20000/hour max-conn 400 bounce-sender bounces+marketing@example.com
<sender transactional@service.example.com> vmta txn-vmta max-msg-rate 3000/hour max-conn 80 bounce-sender bounces+service@example.com smtpd-enforce-spf no smtpd-enforce-dkim no Delivery feedback and notifications delivery-report yes delivery-report-path /var/log/pmta/reports Monitoring / SNMP snmp-enabled yes snmp-port 161 snmp-community public Control API (socket) for runtime control control-listener /var/run/pmta.sock control-auth unix:/var/run/pmta.sock Health checks / auto-restart automatic-restart yes restart-threshold 3 -- end of file --