Frequently Asked Questions

How much about Unix (or Procmail) should I know before trying to use the SpamBouncer?
What types and versions of Unix are supported with the SpamBouncer?
What versions of Procmail are supported with the SpamBouncer?
What is the SpamBouncer "Procmail 3.22 Fix" version for?
Can I use the SpamBouncer on my Windows computer?
Can I use the SpamBouncer on my Macintosh?
What is a "housekeeping update?"

How much about Unix (or Procmail) should I know before trying to use the SpamBouncer?

More than you do. Seriously, you should not attempt to install and configure the SpamBouncer unless you understand the following:

The Unix shell. You should be comfortable working at the Unix shell (Unix command line), and understand how to perform basic tasks. These include:

Navigating between directories (folders)
Listing the contents of a directory
Displaying a text file on-screen
Executing a program
Editing a text file using a Unix text editor (such as vi or emacs)
Creating and deleting files and directories
Unarchiving a standard Unix compressed TAR file (a file ending with .tar.Z or .tar.gz)

In addition, you should understand the basic differences between different types of Unix shells, and understand the common parameters set in the Unix shell configuration files (specifically, the .profile file for Bourne shell variants, and the .cshrc and .login files for cshell variants).

Your email software. You should understand how to set up and configure your email software to retrieve email from your server (if you use a POP or IMAP client) or read email directly on your Unix shell, and how to set up your client to filter email based on the headers in it. (If you use a POP or IMAP client, you will probably want to create folders for different types of email, and filters to sort your incoming email.)
Procmail. You should understand how to set up your Unix account to filter email using Procmail, how to write a simple Procmail script (or recipe), how to edit the collection of Procmail recipes that constitutes your local Procmail configuration file (the .procmailrc file), and what the Procmail log is and how to find it.

If you are not sure what these things are, or how to get started, DO NOT attempt to install and configure the SpamBouncer until you either learn this information yourself, or find someone who does understand it to help you.

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What types and versions of Unix are supported with the SpamBouncer?

The SpamBouncer is currently being developed on and tested on OpenBSD (versions 3.3 and 3.4), RedHat Linux (version 2.4), Fedora Core Linux (version 2.4), and Solaris (versions 8 and 9). In addition, SpamBouncer users have reported running the SpamBouncer (version 2.0 and above) successfully under various versions of DEC Ultrix, FreeBSD, HPUX and AIX, in addition to so many flavors and versions of Linux that I've lost count.

In short, if you run any version of Unix that supports any version of Procmail from 3.11 on, you should be able to run the SpamBouncer.

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What versions of Procmail are supported with the SpamBouncer?

The SpamBouncer runs under Procmail version 3.11 or later.

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What is the SpamBouncer "Procmail 3.22 Fix" version for?

Certain releases of Procmail 3.22 have the so-called "recipe header flag bug". This bug causes Procmail to ignore all but the first set of recipe header flags during a single Procmail session. (Procmail gets "stuck" and assumes that all subsequent recipes use the same set of header flags as the first recipe.) This bug results in false positives (non-spam being flagged as spam), false negatives (spam being flagged as non-spam), and a bunch of outright wierd behavior in the SpamBouncer and most other Procmail recipes.

Fortunately, it is possible to write Procmail recipes that this version of Procmail will process correctly. These recipes are a little bulkier and run a little slower than standard Procmail recipes, so most users whose systems are not running a buggy version of Procmail 3.22 do not want to get the "Procmail 3.22 fix" version of the SpamBouncer. Users whose systems are running a buggy release of Procmail 3.22 MUST use the bug-fix version if they do not want to have all sorts of serious problems.

Unfortunately, there's no certain way but trial and error to verify whether a particular build of Procmail 3.22 is fixed or not. Certain Linux builds have the fixed version, and state so explicitly in the version notes. If you obtain the fixed version from an archive listed on the Procmail home page, you can also be sure that your version of Procmail 3.22 does not have this bug.

If you do not know whether your version of Procmail 3.22 is fixed, however, and cannot install a known fixed copy of Procmail 3.22, you should use the "Procmail 3.22 fix" version of the SpamBouncer, just to be sure. That version will work properly even if your copy of Procmail 3.22 is fixed.

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Can I use the SpamBouncer on my Windows computer?

You can. You probably don't want to. To install the SpamBouncer on a Windows computer, you must do the following:

Install CygWin. You must install the CygWin Unix emulation program, a program that allows developers to create versions of their Unix shell programs to run under Windows. (If you don't know what a "shell program" is, stop here. You do not want to try to install the SpamBouncer on your Windows computer -- trust me on this.)
Create Unix accounts. You must create a "root" account for administering CygWin, and at least one CygWin user account to receive and process your incoming email.
Install the necessary Unix packages. You must install the fetchmail, sed, and sendmail packages, all available for download from the CygWin web site, and get them working properly. In particular, you must configure fetchmail to retrieve your email from your POP or IMAP server.

In addition, you probably want to install a Unix-based email program of your choice. In addition to the Unix command-line mail utility, the mutt and pine email programs are available. It is reportedly possible to configure Cygwin to deliver to Windows-based email programs, but I have not done it or seen it done yet.

Install Procmail. You must install the procmail package, also available for download from the CygWin web site, and configure it to interface properly with fetchmail, so that incoming email is filtered by procmail before being delivered to your mailbox.
Install the SpamBouncer. Finally (are we there yet?) you must install and configure the SpamBouncer.

In other words, to run the SpamBouncer on a Windows computer, you must install and configure a complete Unix shell emulation environment under Windows first. I have never tried this myself. I know that it works only because one long-time user has done it and reported to me how he did it.

I am also absolutely certain that Procmail runs considerably more slowly on a computer running Microsoft Windows (any version) that it would on the exact same computer running any flavor of Unix compatible with that computer. If Procmail runs considerably more slowly, the SpamBouncer is also going to run considerably more slowly. The SpamBouncer is a big program; it is effective, but not particularly fast. If you run it on a Unix server instead of your local Windows computer, it will run faster and eat up less of your system resources.

In short, although it is possible to run the SpamBouncer under Windows, most people will find it too much hassle. Most users who must filter their email on a Windows computer will be much happier using a program designed to run under Windows. I have a list of decent Windows-based spam filters on the Spam Filters page in the Spam Fighting Resources section of this web site.

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Can I use the SpamBouncer on my Macintosh?

If you run Macintosh OSX (any version), you can. OSX is a variant of the Unix family called "Berkeley Standard Distribution" (BSD), with the Macintosh GUI on top. A Macintosh running OSX is therefore a Unix computer, and can run almost any Unix-based shell program. The SpamBouncer requires only Unix shell programs and runs in the Unix shell; it does not require any GUI software.

But you might not want to. Installing and configuring a Unix shell program is nothing like installing and configuring a native Macintosh program. You need to be comfortable working at the Unix shell, understand compilers and how to build a program from source code, know how to create Unix accounts and configure them to send and receive email, and understand how to set up your Macintosh's underlying Unix shell system to retrieve and process email.

In addition, as far as I know you cannot configure the SpamBouncer or Procmail itself to deliver email directly to your native Macintosh email programs. If you choose to use the SpamBouncer, you can do one of two things:

You can install and use a Unix-based email program.
You can create a separate account on your Macintosh to receive and filter email, and to run a POP or IMAP server. You can then configure your Macintosh email client to retrieve email from the local POP or IMAP server, just as it currently retrieves email from a remote POP or IMAP server.

For those reasons, I recommend that Macintosh users who are not also Unix geeks (most of you) choose a different spam filter. I have a list of good native Macintosh spam filters on the Spam Filters page in the Spam Fighting Resources section of this web site.

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What is a "housekeeping update?"

A housekeeping update is an update to the SpamBouncer that contains bug fixes and/or the following:

Viruses list. Email virus detection recipes. These recipes are not a substitute for a good anti-virus program on a user's workstation, but they catch virus emails on the server, allowing you to dump them immediately and preventing them from wasting further resources.
Dangerous Content list. Recipes to catch executable content and other email content that could be an unknown virus or trojan.
Spam Sources list. Recipes that detect email from known spam sources that are either too new or too small to warrant a recipe of their own.
Unclassified Body IPs. Recipes that detect email containing URLs or email addresses hosted at IPs that belong to spammers, but that are too new or too small to warrant a separate recipe of their own.
Spam Haven Domains list. Recipes that detect email that contains domains known to belong to spammers.
Spam Haven URLs list. Recipes that detect email with URLs at non-spam domains that belong to spammers, usually URLs at large free web hosting sites. Many spammers use such URLs to redirect to their real web sites and thereby bypass filtering.
Drop-Box Email Addresses list. Email addresses at non-spam domains that belong to spammers, and that are included in the message bodies of spam.
Other minor updates. Updates to the lists of domains or IPs associated with specific spammers, updates to various pattern matching filters, etc.

A housekeeping update contains no new identified spammers (specific spammers tracked and blocked in the SpamBouncer) and no modifications to the program that require you to modify your current configuration. You can simply download such an update, install it, and enjoy the results.

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