Optimizing Email Infrastructure: A Comprehensive Guide to PowerMTA Monitoring 1. Introduction
- What to track:
vmtaqueue sizes, active connections per domain, deferred queue growth rate. - Better approach: Use
pmta show queueevery 5 seconds, but feed that into a time-series database. A growing hold queue over 10 minutes is a crisis; a growing virtual queue over 2 hours is a configuration error. - Alert trigger: If the active queue grows beyond
max-smtp-outfor a specific domain for more than 15 minutes, investigate throttling or DNS issues.
- Monitor for sudden spikes in outbound volume that could indicate compromise.
- Keep file descriptor and ephemeral port usage under watch; exhausted sockets cause silent failures.
Audit Logs:
Track who is issuing pmta commands (like clearing queues) to prevent accidental data loss.