All programmers are optimists—these words of wisdom were written down almost thirty years ago by Frederick P. Brooks, Jr. The Postfix mail system is a fine example of this. Postfix started as a half-year project while I was visiting the network and security department at IBM Research in New York state. Although half a year was enough time to replace the mail system on my own workstation, it was not nearly enough to build a complete mail system for general use. Throughout the next year, a lot of code was added while the software was tested by a closed group of experts. And in the five years that followed the public release, Postfix more than doubled in size and in the number of features. Meanwhile, active development continues.
One of the main goals of Postfix is wide adoption. Building Postfix was only the first challenge on the way to that goal. The second challenge was to make the software accessible. While expert users are happy to Read The Friendly Manual that accompanies Postfix, most people need a more gentle approach. Truth be told, I would not expect to see wide adoption of Postfix without a book to introduce the concepts behind the system, and which gives examples of how to get common tasks done. I was happy to leave the writing of this book to Kyle Dent.
Just like Postfix, I see this book as a work in progress. In the time that the first edition of the book was written, Postfix went through several major revisions. Some changes were the result of discussions with Kyle in order to make Postfix easier to understand, some changes added functionality that was missing from earlier versions, and some changes were forced upon Postfix by the big bad ugly world of junk email and computer viruses. Besides the changes that introduced new or extended features, many less-visible changes were made behind the scenes as part of ongoing maintenance and improvement.
This book describes Postfix Version 2.1, and covers some of the differences with older Postfix versions that were widely used at the time of publication. As Postfix continues to evolve, it will slowly diverge from this book, and eventually this book will have to be updated. While it is a pleasure for me to welcome you to this first edition, I already look forward to an opportunity to meet again in the near future.
|Hawthorne, New York|
|September 19, 2003|
 Frederick P. Brooks, Jr.: The Mythical Man-Month: Essays on Software Engineering, Addison Wesley, 1975.