<virtual-mta vmta-hot-2> smtp-source-host 203.0.113.11 vmta-hot-2.yourdomain.com
Keep your PowerMTA installation up to date to protect against known vulnerabilities and ensure you have the latest features.
smtp-listener 0/0:25 # Listen on all IPs, port 25 smtp-listener 0/0:587 # Common port for client injection sample powermta configuration file hot
<domain gmail.com> max-smtp-out 15 max-msg-rate 30/s use-rs yes smtp-starttls required </domain>
<!-- Safety net: Don't overload the server CPU --> <max-cpu-usage>90</max-cpu-usage> <virtual-mta vmta-hot-2> smtp-source-host 203
# MTA settings mta_bind_address = "0.0.0.0" mta_bind_port = 25
domain-key my-domain,*,/etc/pmta/dkim/private.key This automated response protects your IP reputation from
<source 127.0.0.1> smtp-service yes always-allow-relaying yes process-x-virtual-mta yes max-message-size 0 </source>
When Microsoft's servers get overloaded or notice a sudden spike in your volume, they will issue temporary 4xx errors (throttling). The back-off-mode normal directive tells PowerMTA to automatically lower the max-msg-rate to a safer threshold (e.g., 100 emails per hour) and increase the retry window when these specific errors are detected. This automated response protects your IP reputation from degrading during a transient block. Essential Prerequisites for Hotmail Delivery