Sample Powermta Configuration File -

Using use-starttls yes is essential for 2025 inboxing standards. 5. Bounce and Feedback Loop (FBL) Processing

# SMTP Macros (variables to make configuration easier) # Define your IP addresses here for easy reference later <define ip-main> 192.168.1.10 </define> <define ip-pool-1> 192.168.1.11 </define> <define ip-pool-2> 192.168.1.12 </define> sample powermta configuration file

# ALWAYS VERIFY PERMISSIONS: # "relay" allows sending to external domains. # Do NOT allow 0.0.0.0/0 unless you want to be an open relay! relay true </source> Using use-starttls yes is essential for 2025 inboxing

dnsbl zen.spamhaus.org { reject-message "Your IP is blacklisted - see spamhaus.org" reject-on-failure yes timeout 5s } # Do NOT allow 0

If you are writing a paper or thesis, you can reference this configuration and discuss:

bounce-processing { process-bounces yes bounce-return-top 50 # Include up to 50 original headers detect-loop yes max-bounce-rate 10% # If >10% bounce, throttle sending bounce-suppression 7d # Suppress addresses bouncing for 7 days }

This write-up provides a solid foundation for setting up a PowerMTA instance. Always consult the official Port25 documentation for advanced features like HTTP injection or detailed pattern matching for bounces.