Postfix vs. Sendmail

Postfix and Sendmail are in the same category of Mail Transfer Agents. When selecting the MTA (Mail Transfer Agent) for your system, to choose the best option that meets your needs, you must consider a few important features, such as performance, security, documentation, and feasibility. The following points are given, based on which you can explore some technical aspects of MTAs:

  • More than one configuration file
  • Minimal syntax
  • Which type of scripting language is used
  • Check code stability
  • Source code contribution
  • Set of minimum features

In this article, you will learn about the basic idea of both Postfix and Sendmail. You will also see some common differences between Postfix and Sendmail.


Postfix is the most commonly used free and open-source MTA (Mail Transfer Agent) used for deciding routes and delivering emails. It is a cross-platform email server that can be installed on most UNIX like operating systems. Postfix consists of many server and client programs, in which server programs are mostly running in the backend and client programs are invoked by the system administrator or user programs.


  • Security-oriented mail server
  • Provides detailed documentation
  • Works well in high queuing operation
  • Provides Sendmail compatibility
  • Active development
  • Cconfiguration is simple, according to configuration file parameters


  • Difficult to customize according to user requirements


Sendmail is a general-purpose MTA used for email routing. It supports different kinds of email transfer and mail delivery methods, in which SMTP (Simple Mail Transfer Protocol) is used to transport emails over the Internet. Some of the pros and cons of Sendmail are given below:


  • Portability
  • Flexibility
  • Easy to configure


  • Difficult to customize
  • Inadequate security mechanism

Postfix vs. Sendmail – Comparison

Postfix and Sendmail are both MTAs, but the Postfix mail server is security-oriented, whereas Sendmail is a standard mail transfer agent for Unix systems. Based on the following features, we can easily compare some major differences.


The most common difference between these two is architecture. Postfix has a modular architecture composed of many independent small executables. It provides multiple options, parameters, and features. In contrast, Sendmail has a monolithic design that uses a single process always running at the backend. Sendmail is dying out in comparison to Postfix because many prefer the architecture of Postfix.


In comparison to other MTAs, Postfix emphasizes security. Postfix is much more secure than Sendmail, which has weak security architecture. Postfix is designed to overcome the vulnerabilities that are associated with Sendmail. Moreover, a good Postfix configuration secures sensitive data from spam, abuse, and leakage.


Sendmail is not great in terms of its performance, making it a poor competitor. Postfix has a queue manager that handles the queuing much more quickly. Some administrators claim that even with a high load, Postfix is more efficient than Sendmail.


Sendmail is not more efficient than its competitor, Postfix. Therefore, it is not very reliable. Postfix is designed to replace Sendmail. Postfix is more reliable due to its modular architecture. It consists of independent components that can be easily changed in case of any problem. This is why Postfix provides such high-level reliability.

Administration or Flexibility

Postfix provides ease of administration and a high level of flexibility. For beginners, it is easy to administer and set up, as compared to other MTA services. Moreover, Postfix also supports the Sendmail command-line interface and is compatible with various mail filters of Sendmail. Sendmail loses to Postfix in terms of usability and flexibility. In practice, it is not a good choice for installing Sendmail MTA. But, at the same time, it is already installed on most Unix operating systems. Sendmail is a portable MTA. However, it can be used on non-Unix, OS-like windows. That is the reason why some people opt for Sendmail instead of Postfix.


This article briefly provided a comparison between Postfix and Sendmail. Sometimes, you may not need to restrict yourself to using only one MTA. When you do not want to design a new email server from scratch, then you can use Sendmail. But, in terms of performance, security, and other features, you might come to prefer Postfix MTA. You can choose either MTA, according to your requirements and preference.

About the author

Karim Buzdar

Karim Buzdar holds a degree in telecommunication engineering and holds several sysadmin certifications. As an IT engineer and technical author, he writes for various web sites. He blogs at LinuxWays.