KumoMTA is the only true Open-Source PowerMTA alternative, capable of matching performance of several million messages per hour while providing granular traffic shaping configuration and automation across unlimited IPs.
Free PowerMTA Alternatives
The best free alternative to PowerMTA is KumoMTA, which is also Open Source. If that doesn't work for you, our users have ranked 1 alternatives to PowerMTA, but unfortunately only one of them is free. If you can't find an alternative you can try to remove all filters.