SpamAssassin

Excellent guide to SpamAssassin!

A comprehensive description of the many features of SpamAssassin [SA] and how it can be integrated with the major mailing programs sendmail, postfix, qmail and Exim. Certainly, the free and open source nature of SA will appeal to some.But the problem with the book is that it never seriously analyses the many flaws of SA. The most glaring is how it used blacklists. It only applies these against various header fields. Yet it is well known that spammers forge arbitrary sender addresses. Which greatly reduces the efficacy of the blacklist.Also, the book devotes attention to how SA uses Bayesians. It says how you need a corpus of spam and one of non-spam, to train the Bayesian. Yet this has proved to be a severe constraint on actual usage. The book never says how these corpuses are to be found. In practice, this is done manually. Even worse, the book does not point out that spammers can and are poisoning Bayesians, with innocuous non-sequitur words in their messages. This means that a Bayesian must be continually retrained on new corpuses, that have been manually gathered. Very labour intensive. Few users are willing and able to do so.

SpamAssassin is the immensely popular open-source spam solution for the Linux/Unix world. This book covers version 3.0, which, curiously enough, is not included with the book. This is pretty unusual in the open-source world since it costs very little to put a copy of the program onto CD and bind it into the book.The reasons for SpamAssassin's popularity include its high level of customizability, the ability to change the rules and the weights assigned to those rules, automatically report spam to clearinghouses, ability to interface with other resources on the internet including DNS blacklists, ability to create a whitelist, and the ability to work with a wide variety of mail systems including sendmail, Postfix, qmail, and Exim. One of the really nice features is the ability for the system to automatically add a person to the whitelist if you send an outgoing email to that person.Of course all of this requires an understanding of how SpamAssassin works and how to configure and tweak it to get it to do what you want. That is where this book comes in. The author has done an excellent job of explaining not only the concepts but also the details of how SpamAssassin works and how to tweak it to work best in your environment. This is easily one of the most clearly written and understandable books on configuring the software that I have read. SpamAssassin is highly recommended for anyone on a Unix-like system who is considering using the program as a spam control solution.It took some time to figure out how to configure it best for my needs but my spam is down over 90% with no false positives. Don't expect the author to spoon feed you what is best for your system, but he gives you the information to design one that works for you.

I'm sure that the Spamassassin developers are doing the best they can, but the sad fact is that the spammers are winning the war.I don't think there really is a good solution for spam right now. Blacklists don't work, Bayesian filters don't work - nothing works well enough to stop spam entirely.Still, Spamassassin is useful, and because it is configurable (and open source), you at least have complete control. That assumes, of course, that you understand how it works. That's the reason to buy a book like this, but I was a bit disappointed in that area. I'm not sure yet whether the fault is Spamassassin - maybe it's just not as configurable as it should be - or this book just not explaining things very well.For example, I note that an awful lot of the spam I get is from certain IP blocks. I don't want to block out large ranges arbitrarily, but I thought it might be interesting to increase the Spamassassin score if the sender was in one of those ranges.Well, if there is a way to do that, I still haven't figured it out. It could be me - maybe I just haven't read things carefully enough - but I didn't feel that I understood Spamassassin after reading this. Maybe this needs to be a bigger book - only about 100 pages are devoted to configuration and modifying rules, the rest is installation advice.On the other hand, there's nothing else out there, and this isn't totally without value. If you are using Spamassassin, you may want to pick this up - it could be a long wait for anything better.

Had high hopes when I got this book. Sadly letdown. The book gives a tired old treatment of using a black list to check against the header of a mail message. Now not all spammers forge the header. But many do, as known for years. And they don't just forge the From line. They can also forge the Received lines.When the author wrote the previous review, he mentioned the Received header lines. But, in general, for an ISP, the only valid header info is what the ISP itself writes. Received lines not written by the ISP can also be forged.So using a black list on a header can easily be defeated by a spammer. And is being done so by many of them.But Schwartz goes on to say that SA can now apply the black list against the body links. GREAT! Awesome. This is the key difference between 3.0 and the earlier stuff. Yet, when I went thru the book, I did not see any mention of this. Okay, perhaps I missed it. But if the book actually talks about it, it is in a very obscure fashion.The new ability in 3.0 is seminal. Because while a spammer can forge headers, if he wants users to click through to his site, he has to write a valid address for himself. When AOL implemented this idea [not using SA] earlier this year, they said it led to the first documented decrease in spam they'd seen.I repeat- if the book didn't mention the new 3.0 ability, it is grossly deficient. If it did mention it, but scantily, ditto. It certainly deserves at least as much space as was given to Mr Bayes.

Ein Buch zum Spamassassin. Hoert sich spannend an, und weil ich auf gedrucktes Wert lege, habe ich es bestellt. Ausgepackt, gelesen, Ernuechterung. Eindeutig eines der schlechteren Werke aus dem O'Reilly Verlag.Mehr als die Haelfte des Werkes beschaeftigt sich mit der Integration in die gaengigsten MTAs.Wie er installiert wird, wird ebenfalls beschrieben. Wer eigene Regeln erstellen moechte, kann sich ueber 32 Seiten freuen. Wie man den Spamassassin trainiert wird auf 22 Seiten erklaert.Mal abgesehen von der Integration in diverse MTAs und der Installation, werden die restlichen Kapitel nur mal eben angerissen. Anleitungen, wie der Spamassassin in den Sendmail integriert wird liegen dem Paket bei, und man findet hunderte Quellen im Internet die einem dies erklaeren, und dafuer muss man nicht mehr als die Haelfte des Buches aufwenden um die Integration in MTAs zu erklaeren.Ich hatte mir ein Buch vorgstellt, in dem dem Mailadmin erklaert wird, wie man den Spamassassin administriert, und darunter faellt fuer mich auch der Bayesche Filter. Leider wird diesem Thema nur 13 Seiten geopfert - eindeutig zu wenig. Nach der Lektuere weiss man, dass es ihn gibt, und wie die Befehle lauten um ihn zu trainieren. Detailfragen bleiben leider unbeantwortet, wie z.B. ob der Spamassassin seine eigenen Header ignoriert (oder man ihm dies beibringen muss) wenn man den Bayeschen Filter trainieren moechte oder ob er seine eigene SPAM Markierung im Subject erkennen und ignorieren wird. Wird er in Zukunft echten SPAM immer noch erkennen, wenn in den falsch erkannten Nachrichten die SPAM Markierungen vorhanden sind?Nach der Installation und Integration in seinen MTA wird dieses Buch im Regal verstauben. Die Erstellung eigener Regeln und das trainieren des Bayeschen Filters werden leider nur zu oberflaechlich angeschnitten, so das man gezwungener Massen auf Anleitungen im Internet zurueckgreifen muss. Und dort findet man auch Anleitungen fuer die Installation und Integration.Wer sich nicht mit selbst erstellten Filtern und dem Training befassen moechte, sollte ueberlegen, ob ihm 25 Euro fuer eine Installations- und Integrationsanleitung wert sind.