They isolate reputation. A marketing campaign issue won’t kill your transactional delivery.
Before tweaking advanced settings, you must understand the configuration hierarchy. PowerMTA reads pmta.conf (usually located in /etc/pmta/ ). The directives follow a strict inheritance model: powermta configuration guide top
VirtualMTAs allow you to map specific "from" domains to specific IP addresses. This is critical for reputation management. They isolate reputation
logrotate /var/log/powermta.log daily missingok notifempty delaycompress compress maxsize 100M maxage 7 postrotate /usr/sbin/powermta reload endscript powermta configuration guide top
statistics-interval 30 <statistics graphite> host monitoring.internal.com port 2003 prefix pmta.prod. </statistics>