May 20, 2016

Posted in:

5 of Our Favorite Things about PowerMTA


One of the many applications we offer at Edge is a service called PowerMTA, an enterprise-class email delivery application. In fact, you may already have it installed—or you may be thinking about using it, but aren’t convinced as to why you need it. Below we’ve listed five of our favorite things about PowerMTA—and how to use them.

Ease of Use

PowerMTA runs on Windows or Linux with a quick and easy step-by-step setup—because it only has three main configuration files. The default installation ships with a basic config file written in an easy to work with, human-readable syntax. PowerMTA also comes with a comprehensive manual describing all commands in detail, a blog at, and forums located at

Web Interface

PowerMTA includes a Web Interface for real-time insight into the health of your Mail Server. Quickly see how many emails are pending, where they are attempting delivery and what queue is sending them. Running commands against the server is also possible after setting the appropriate IP whitelist directives. Keep this screen up while you work to have instant insight into your deliverability rates!




A core concept of PowerMTA is the VirtualMTA. From Port25:

VirtualMTA technology allows senders to control and monitor the source IP address for each single message. Each VirtualMTA performs its delivery functions independently; therefore, as long as the source IP is not blacklisted, your message has a higher chance of being routed to the inbox. VirtualMTAs allow for granular segmentation of your traffic patterns, while offering precise mailing delivery control with options to enable or disable DomainKeys and/or DKIM-based sender authentication.

Essentially, VirtualMTAs allow you to apply your directives either individually or to larger groups of VirtualMTA called VirtualMTA Pools. An example of this granularity is allowing emails containing a certain header, sent from a certain email address, or sent from a certain server to be delivered via specific VirtualMTAs/IP Addresses. Setting up a hierarchal system of MTAs, VirtualMTAs and VirtualMTA Pools gives you absolute control of how your emails route through PowerMTA.

Email Prioritization

Do you ever need some emails to be sent out faster than others? If so, take advantage of the recipient-priority directive! With this feature, password resets and priority communications will occur before emails with a lower priority. For example:

mail-from: recipient-priority=30


mail-from: recipient-priority=100

rcpt-to / recipient-priority=90

Opportunistic TLS

Secure, encrypted offerings have evolved over the past few years to become a must have for all internet services. Recently, Google has moved to disclose when emails are sent to, and from, email servers that do not support encryption. (Click here for more information on that decision.)

With only two directives, you can direct PowerMTA to deliver emails over TLS (SSL) to any receiving mail server that supports the protocol. While not all email servers support this feature, this one change will post your reputation and secure your emails from eavesdropping. For example:

<domain *>

use-starttls true

require-starttls false


Final Thoughts

As you can see, PowerMTA has many great features that you may have never considered before. If you have PowerMTA or are hoping to implement it into your environment, feel free to reach out to us any time! We’re always happy to help.

Written by: Matthew Reid, Implementation Engineer at Edge Hosting

Go back