3 Best Open Source MTA(Message Transfer Agent)

3 Best Open Source MTA Every Email Marketer Should Know About-

Message Transfer Agent or MTA or SMTP server is the most know words for email marketers and email marketing companies. If you are a noob in email marketing industry then you must know about best smtp relay server or MTA for your email marketing needs.A message transfer agent (MTA) is a software application used within an Internet message handling system (MHS). It is responsible for transferring and routing an electronic mail message from the sender’s computer to the recipient’s computer. The basic platform for an MTA is an exchange system with client/server architecture.
Here we are discussing about some best MTA tools and describe ability to handle large sending volume.


Postfix is an open source and free MTA . it is most popular among all known opensource mta because of its ability to handle large volume and queue. it has ability to connect externally developed tool for queue management. Best part of postfix is it’s continue development and improvements.

  1. Resource :  However postfix is not a resource hungry with it’s default configuration but as compare to some other enterprise grade MTAs it uses more resource than usual.
  2. Queue Management : Postfix has strong queue management and can be modified by it’s Before-queue & After-queue filters. You just have to write a simple or a complex program about what you wanted to achieve with queues.
  3. IP Management : Latest stable version of postfix supports both version of IP address. postfix does not support IP rotation by default.
  4. Throttling : However, postfix can be configure to throttle email sending based on recipient domain but you will always find difficult to configure if you do not understand much about postfix configuration.


Indimail is a qmail based complete mail server with lots of great features. Indimail is developed by an Indian Programmer named Manvendra Bhangui. Indimail is a complete suite and should be best choice for opensource lovers. it has all the enterprise grade qualities to be a best MTA for any email marketer or agencies. Truly best part of indimail are regular development & quick support by author in google support group.

  1. Resource : Indimail required average resource to handle queues. however if we increase queue counts (which is a useful feature) it requires more disk & memory resource. a faster disk process indimail queue faster.
  2. Queue Management : Indimail has best queue management in our test. We can increase queue anytime to handle and process large amount of mails. We also can write and integrate external program to achieve different tasks.
  3. IP Management : Indimail support both version of IP. Indimail has strong ip rotation feature by default and is extended to recipient domain based ip separation and rotation.
  4. Throttling : Indimail has builtin throttle feature which required configuration. it is really very easy to configure. Indimail has global and recipient domain based configuration available. 


Postal is very new among well known open source MTAs. It is developed in RoR and work great for transaction mails. it is has ability to track email engagement like open & clicks which found very rarely to any MTA even it is enterprise grade.

  1. Resource : Postal runs on very low resource however only debian based operating system is supported. Ubundtu is best OS to install & run Postal.
  2.  Queue Management : Postal has basic queue management however  has ability to run different SMTP on same instance.
  3. IP Management : Postal support multi-MTA and Multi-IP using IP pool feature.
  4. Throttling : Postal has not IP or domain based throttle available. However, MTA based throttle can be configured. If you are smart enough, you can use it as a great tool.


Sourced from : 171mails Blog
Original content Link : https://www.171mails.com/2018/01/16/best-mta-email-marketer/


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