Postfix: The Definitive Guide

Wietse Venema at the IBM Thomas J. Watson Research Center in New York initially created Postfix (1997) to solve major problems facing all email systems, including commercial email systems still full of holes in 2024. Core vulnerabilities in simple Basic Install allow outsiders to easily read your emails, write forged emails in your account, add fake accounts into your mailboxes, alter & forge messages .. The Mailboxes on wide spread commercial systems use terribly unsafe open access settings by default: to Read, Read/Write, to Write which includes Delete for example. . . In reality an “Email System” is SIX separate applications to provide the functionality in either insecure methods (default) or secure methods (with exacting Custom Configuration of settings sewn together in an electronic workflow to protect YOUR organization). While most people are intimidated with setting up secured email, others are just part of the chancers, cheaters, liars failing to do their job. When you consider IS (programmers) actual tune software & IT workers are just computer appliance installers plugging parts together then declare success when system powers up in skeleton configuration - - The Problem Is Clear. . . *Somebody MUST* find, create, connect ALL the settings in complete automation workflow. - Just running simplified generic “load & go” installation IS NOT Safe by Default. *TRUE FACT* Security Costs Are Higher Than Purchase Price of Software, therefore Nothing is secure by default except BSD Unix with nothing running. ** The solution for WHAT to do, HOW to perform each task, WHICH SETTING Value to use & HOW to VERIFY your assembly of settings ARE WORKING IN SECURE ADVANCED MANNER is contained in this wonderful classic DIY Postfix guide version 2.2. while newer edition is available for version 2.4 the differences are small. *** As mentioned in this review are The SIX Email Component Applications for Global/Major/Minor Organization to actually be running a Truly Secure SPAM-Free Email System: 1) Postfix - to transfer mail between organisations with event logging to database, 2) Dovecot IMAP to provide ‘virtual’ Mailboxes using “vhost” for each user to block direct access, 3) Client end-user mailbox application - to download, read, write, delete, manage individual emails on your laptop, 4) ClamAV Email Antivirus inbound scanning “incoming” emails for malware, 5) ClamAV Email Antivirus outbound scanning to prevent sending out emails carrying malicious undetected infections to other organisations & clients, 6) SASL Security Authentications over internet for safer communications between Postfix <to/from> Dovecot IMAP mailboxes with Sieve/SpamAssassin scoring/discarding spammer email which is which is what Barracuda Networks also uses, then <to/from> Whatever Enduser Email Client Application ACCESSING/SENDING Your Emails (Libre, Roundcube, Thunderbird, Applemail, MS-Outlook). ** Plus ** (Application #7) is using DNSSEC Networked Device Authentication for positive Verification you are electronically connecting to Real Honest Systems & NOT the Fake, Hacker, Criminal Frauds as there are literally MILLIONS of fakes running 24x7 at 65 million instructions per second - faster than you can think or read. THIS book explains background, architecture design, with fully functional advanced setup in 9 short chapters of 8-10 pages on properly configuring each feature. Plus excellent appendix on Setting parameters, using Postfix commands, compiling Postfix and FAQ. - - you might consider the benefit of setting up Testing/Learning/Standby Postfix install with separate Postfix install for daily use. We have been using Postfix very successfully at multiple corporations since 2007. TIP: Postfix needs Dovecot IMAP so you should get too Dovecot book too for a complete setup. > >Semper Fidelis, DC

After over a month of trying to get my first email server up and running using the try a setting, see what happens method, I finally gave up and bought this book. Now I'm in business. Everywhere I read, people claimed the easiest to configure MTA was postfix, so that is why I began to use it. True, the documention on the website is helpful and so are the included examples, but if you don't have the concepts down, that is useless. Thats where this great book comes in. This book isn't just a paper copy of the online docs, unlike most other computer books. It explains what stuff is, does, and what it means. I can read the config file just fine, I just don't know what the settings do. For example, the online docs showed how to setup masquerading and examples, but never told me what that meant. From a newbie standpoint, the masquerade meant the same thing as an alias. Well, those words mean the same thing. I need the vocabulary from the book to help me understand. Conanical is a common work in computer land? Maybe in Silicon Valley but not in NJ. A glowing chapter is DNS and e-mail which more than pays for the entire book. Not only to I understand DNS better, I can setup a backup mail system. Another great thing is the author shows you an entire setup zone file in one chunk, instead of line by line explanations and never showing you the whole thing put together. DNS and Bind book anyone? For shame. Also, The Hosting Multiple Domains is a fantastic chapter. Anyways, if you are lost and feeling like and idiot like I was, get this book. Thanks Mr. Dent for a fantastic book that is clear and easy to understand.

After getting my Postfix server running using online documentation I knew that I had been guessing, and that I would need help to go farther. I started reading the Blum book on the subject, and learned a few things, but I was no less confused.With Dent's "Postfix: The Definitive Guide" I found what I needed. I have a much clearer understanding now, and I have been able to extend some of the sample code to things I want, such as accepting mail from certain domains on a per-user basis. Highly recommended.

Over 20 years ago, Eric Allman wrote sendmail to handle the then tricky problems of email on BSD and SystemV unix machines. Since then, email has become all pervasive to educated persons. En route, sendmail also grew vastly in complexity to handle this. So much so that just manipulating its configuration files became convoluted. Worse yet was the actual debugging of its source code.Despite all this, sendmail is still the most powerful Message Transfer Agent on unix/linux. But Venema recently tried a totally different approach. From the onset, he used a modular design and a set of 5 queues in which to process messages. In essence, we have a finite state machine, where the state of a message is the queue that it is in. Dent here shows how Postfix is fundamentally a queue management system. Analogous to how any operating system is basically a file management system. The hope is that Postfix will be easier to maintain and debug. Certainly, from a sysadmin's viewpoint, the configuration files seem simpler than sendmail's. But perhaps this is partly because Postfix does not yet have the full capability of sendmail?As a sign of the times we live in, Dent devotes 2 chapters to antispam measures possible in Postfix. This is equivalent functionality to sendmail's Milter API. Likewise, the current Postfix antispam implementations are no more effective than Milter's. Which leaves room for you to try your hand at improving this state of affairs!As Dent describes, Postfix is now open source and easily available. Still not as widely installed as sendmail. But you now have a credible alternative to it.

I remember folk on the Postfix mailing list complaining about how long it was taking for this book to be written. Well, I've been writing a computer book for the past year and all I can say is 'I feel your pain Kyle'. Anyway, the wait has been well worthwhile, and possibly a benefit because the book deals with several new features only recently added to Postfix. You know that an O'Reilly book is at least going to be half-decent, and possibly excellent. In this case Mr. Dent's work has hit the mark spot on, and to my mind earns an excellent rating. Why ? Well, first of all his writing style is clear, concise and easy to read. Secondly he's covered everything you'd want to know about Postfix, rather than an easy feature subset. And third, he's avoided the common pitfall with software guide books where the writer simply presents a jazzed-up version of a reference guide---lists of configuration parameters and their explaination making up the bulk of the book.Kyle takes the time, and it's much appreciated by the way, to explain how Postfix features work, why they exist (very important), and when they should be used (or not used). I was particularly overjoyed to see that he has covered the configuration of the server to support both SASL and TLS. I'm sure that those chapters will save me _days_ of hair pulling in crypto-hell.In summary: If you already run Postfix, and you're not Wietse Venema (well, I'm sure he has a complimentary copy already), then RUN out and buy this book. If you don't run Postfix, but were thinking of changing to a better MTA, then consider your options again because now that this book exists, Postfix is a more attractive choice for many admins. Even if you don't ever plan to run Postfix, this book is a pretty good read for those who are just plain interested in e-mail technology.

I have been trying to convert over to Postfix for the last few months using online documentation. Kyle Dent has done a GREAT job explaining all the aspects of how to configure Postfix and make Postfix do what you want. The examples in the book are just what I needed to understand the complex configurations I wanted to install. I was able to get maillist working, virtual domains, virus and spam testing all integrated with a MySQL backend. I am very happy with this book and would HIGHLY recommend it to anyone trying to get Postfix up and running.