Sample Powermta Configuration File -

domain-mapping *.edu { max-smtp-out 2 max-msg-rate 500/h throttle-delay 200ms } DKIM Signing --------------------------- dkim-sign domain example.com selector1 dkim-keyfile /etc/pmta/dkim/example.com/selector1.pem dkim-identity @example.com dkim-headers From:To:Subject:Date:Message-ID dkim-signature-expiration 7d dkim-sign

# Custom throttles for ISP reputation domain-throttle hotmail.com max-msg-rate 10000/h max-conn 15 domain-throttle outlook.com max-msg-rate 10000/h max-conn 15 domain-throttle live.com max-msg-rate 8000/h max-conn 10 virtual-mta sample powermta configuration file

dkim-sign domain example.org default dkim-keyfile /etc/pmta/dkim/example.org/default.pem dkim-identity @example.org dkim-sign dkim-sign-policy * { sign-control * dkim-sign(example.com) # Default } --------------------------- Authentication (SPF, Return-Path) --------------------------- auth-domain example.com # Bounce handling domain (different from sending domain) bounce-domain bounce.example.com bounce-address bounces@bounce.example.com spf-identity mfrom spf-pass-action none spf-fail-action tag auth-domain domain-mapping *

virtual-mta bulk-low-priority smtp-service outbound source-ip 192.0.2.30 max-smtp-out 5 max-msg-rate 5000/h throttle-delay 100ms # Inject delay per message virtual-mta Outbound SMTP Service --------------------------- smtp-service outbound type outbound max-smtp-out 100 # Global cap across all vMTAs max-msg-rate 100000/h max-conn-per-domain 20 bounce-handler http://localhost:8080/bounce # HTTP bounce processor feedback-loop-handler http://localhost:8080/fbl use-starttls yes require-tls false dns-timeout 15s resolve-command /usr/bin/dig +short smtp-service --------------------------- Domain & ISP Specific Rules --------------------------- Fine-tune for major receivers to avoid rate limits and blacklisting. domain-mapping * { # Default for all domains max-smtp-out 10 max-msg-rate 10000/h max-conn-per-domain 5 throttle-startup 10 throttle-inc-interval 10s } sample powermta configuration file

domain-mapping yahoo.com { max-smtp-out 8 max-msg-rate 5000/h max-conn-per-domain 4 use-starttls yes require-tls false rcpt-to-nxdomain-limit 3 }

(For High-Volume Production Email Delivery) # ------------------------------------------------------------------- # PowerMTA Configuration File - Sample for High-Volume Email Delivery # ------------------------------------------------------------------- # Version: 4.5+ # Purpose: Production-ready configuration with deliverability tuning # Notes: Adjust paths, IPs, domains, and resources to your environment. # ------------------------------------------------------------------- --------------------------- Global Process Directives --------------------------- process-id-file /var/run/powermta/pmta.pid spool-directory /var/spool/pmta log-directory /var/log/pmta max-smtp-out 100 # Max concurrent outbound connections (all MTAs) max-errors-per-domain 10 # Failures before marking domain dead max-errors-per-recipient 3 domain-error-expiration 30m # Retry dead domain after 30 minutes recipient-error-expiration 30m --------------------------- SMTP Service (Inbound) --------------------------- smtp-service port 25 access-source config # Use IP-based rules below access-rule allow 127.0.0.1 access-rule allow 192.168.1.0/24 access-rule deny all