Update: Switching from Postfix to PowerMTA: Here is what you need to know… | Port25 Solutions, Inc.
Fred Tabsharani

By port25admin

Update: Switching from Postfix to PowerMTA: Here is what you need to know…

Recently we had a large ESP switch from Postfix to PowerMTA.  Here is what you need to know.

I’ve written a Whitepaper and a couple of follow up blog posts on the benefits of PowerMTA vs. Open-Source tools, but many reasons still exist far beyond what’s been published.  Every demanding sender depending on their sending environment has their own sets of reasons to switch.  I’ll try to outline a few of the latest reasons to switch in todays senders marketplace.

Some pundits believe that the single most important difference between Open-Source and CommericalMTAs is the “visibility” into granular deliverability information.  While the technology is also different, the use of information that is disseminated from PowerMTA reporting and monitoring features is far more important in order to instantly react to potential deliverability issues.  That’s what matters most to delivery professionals and system admins.   The innate quality of this information, for example, the understanding about queues and delivery periods of these queues, along with ISP responses within these queues is merely one example to the myriad of deliverability keys.  Here are some other critical factors to consider:


Server uptime is the most critical aspect of sending digital messages, especially in a marketing automated world.   This requires continuous monitoring and management by server administrators of the PMTA application.  Server uptime depends on email data being available to administrators that allows them to foresee potential blocks, ISP throttling and/or junking.  These tools deliver vital data about hardware and operating system performance in real-time to administrators, alerting administrators when something goes wrong and ultimately preserving IP reputations.

To give you a sense of PowerMTAs uptime performance,- today-we conducted an informal twitter poll, and found out that the average uptime for a PowerMTA user is 284 days without a restart.  More later on this in a separate blog post.  Some clients haven’t had to restart their PowerMTA application since the last upgrade, almost two years ago.   So, in our mission critical delivery processes, zero downtime is essential.  You literally never have to restart the application. Now, scaling with open-source systems can be a challenge, and when the server reaches exhaustion, it can become unusable and may take hours for a resolution.


Along with uptime comes support with commercial grade MTAs.  Within the PowerMTA network, customers experience responses within minutes of accessing our forum or making a simple call to support.  It would be a challenge to find a similar service offering in an open-source world.  At the end of that day it is the uptime and reliability, dependability and scalability of PMTA that’s going to give you peace of mind, which is exactly what you want your MTA to do.

Connection Limitations

Open Source systems (tools) are winners with start ups, but are not necessarily meant to manage the unique sends of large senders and ESPs.  Open Source tools don’t allow you to configure the number of connections to open, or set the number of simultaneous connections, nor do they provide the number of delivery attempts per hour, when throttling.  Given today’s explosion with automated marketing systems, configuring connection directives becomes more vital than ever as mature ESPs are distinguished by their marketing automation tools and strategies.   In addition, PMTA has the ability to break connections for lower priority queues.

Bounce Management and Classification

Managing bounces is another critical aspect to consider when choosing between open-source and commercialMTAs.  Open source tools lack this critical building block especially when the system can’t identify the next retry period and/or to set limitations on the different types of bounce classification.  In order to process bounces in the right way they first need to be classified, and PMTA has many different built in categories and different types of bounces and what to do with them once encountered, right out of the box.   Once classification occurs, you can apply rules to them, unfortunately open source systems don’t have these rules in place.  A good rule is that invalid email addresses are immediately disabled and excluded from further mailings. Other bounce types should be removed as soon as it is clear that the problem is permanent. Spam related bounces should be detected and require action from the sender to resolve them.

There are literally hundreds of more reasons to switch and it all depends on your budget, and your vision of your composite sending trajectories.  Evaluate PowerMTA, and see if its the right fit for your sending environment and join 70% of the ESP market.



9160 Guilford Rd // Columbia, MD 21046 // (410) 750-SMTP