The Postfix MTA

Several MTAs are available for Linux. Historically, the most common MTA on Unix has been sendmail, which has been around for a long time. It is generally considered somewhat more difficult to use than the alternatives, but it is thoroughly documented in the book sendmail, by Bryan Costales with Eric Allman (O’Reilly).

Postfix is a newer MTA, developed by security guru Wietse Venema as a replacement for sendmail. It’s designed to be compatible with sendmail but to provide a higher level of security and be easier to configure.

Postfix is a highly flexible and secure piece of software that contains multiple layers of protection against would-be attackers. Postfix was also written with performance in mind, and employs techniques to limit slower activities such as creating new processes and accessing the filesystem. It is one of the easier email packages to configure and administer because it uses straightforward configuration files and simple lookup tables for address rewriting. It is remarkable in that it is simple to use as a basic MTA, yet still able to handle much more complicated environments.

Many Linux distributions have Postfix built in, so you may already have it installed on your system. If not, you can find prebuilt packages or compile it yourself from the source code. The Postfix home page ( contains links to download both the source code (“Download”) and packages for different Linux distributions (“Packages and Ports”).

Postfix has two ...

Get Running Linux, 5th Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.