$Id: README,v 1.101 2006/08/18 15:00:31 jonz Exp $

DSPAM v3.8 <jonathan@nuclearelephant.com>
Copyright (c) 2002-2006 Jonathan A. Zdziarski
http://dspam.nuclearelephant.com

Classifier Version: 380

LICENSE

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; version 2
of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

CREDITS

DSPAM Development Lead
  Jonathan A. Zdziarski <jonathan@nuclearelephant.com>

PostgreSQL Driver Maintainer
  Rustam Aliyev <rustam@azernews.com>

Patch Contributors (Past 6 Months)
  Feb/2006 Cove Schneider <cove@wildpackets.com>
  Jan/2006 Norman Maurer <nm@byteaction.de>

TABLE OF CONTENTS

General DSPAM Information

  1.0 About DSPAM
  1.1 Installation and Configuration
  1.2 Testing
  1.3 Troubleshooting
  1.4 DSPAM Tools
  1.5 Agent Commandline Arguments

Advanced DSPAM functionality

  2.0 Linking with libdspam
  2.1 Configuring groups
  2.2 External Inoculation Theory
  2.3 Client/Server Mode
  2.4 LMTP 
  2.5 DSPAM User Preferences
  2.6 Fallback Domains

Miscellaneous

  3.0 Bugs, Ports, and the like 
  3.1 CVS Access

1.0 ABOUT DSPAM

DSPAM is an open-source, freely available anti-spam solution designed to combat
unsolicited commercial email using advanced statistical analysis. In short,
DSPAM filters spam by learning what spam is and isn't. It does this by learning
each user's individual mail behavior. This allows DSPAM to provide 
highly-accurate, personalized filtering for each user on even a large system 
and provides an administratively maintenance free solution capable of learning 
each user's email behaviors with very few false positives.  

While DSPAM is focused around spam filtering, many have found alternative
uses for all types of two-concept document classification. 

DSPAM is rapidly gaining a large support forum and being used in many large-
scale implementations. Contributions to the project are welcome via the 
dspam-dev mailing list or in the form of financial contributions. 

Many of the foundational principles incorporated into this software were
contributed by Paul Graham's white paper on combatting spam, which can be
found at http://paulgraham.com/spam.html.  Much research and development has
resulted in many new approaches being added onto the DPSAM project as well,
some of which are explained in white papers on the DSPAM home page.

DSPAM can be implemented as a total solution, or as a library which developers 
may link their projects to the dspam core engine (libdspam) in accordance with 
the GPL license agreement.  This enables developers to incorporate libdspam as 
a "drop-in" for instant spam filtering within their applications - such as mail 
clients, other anti-spam tools, and so on.

PLEASE NOTE: DSPAM and libdspam are distributed under the GPL license, not the 
LGPL. Commercial licensing is available for those who seek to redistribute
DSPAM or some of DSPAM's components/libraries in their non-GPL products.
Please contact jonathan@nuclearelephant.com for more information about
commercial licensing.

The DSPAM package is split up into the following pieces:

DSPAM AGENT

The DSPAM agent is the command center for all shell and daemon operations.
If you're using DSPAM as a filtering solution, this is the 'dspam' (or dspamc)
binary you're likely going to be talking to via commandline. 

LIBDSPAM: CORE ENGINE

The DSPAM core processing engine, also known as libdspam, provides all critical
spam filtering functions.  The engine is embedded into other dspam components
(such as the agent) and is responsbile for the actual filtering logic.
If you're not a developer, you don't need to be concerned with this component 
as it is automatically compiled in with the build. 

WEB UI

The Web UI (User Interface) is designed to allow end-users to review their
spam quarantine and history, graphs, and to delete their spam permanently.
They can also optionally use the quarantine to perform all of their training.
The UI also includes some basic administrative tools to change settings and
manage user quarantines.
 
TOOLS

Some basic tools which have been provided to manage dictionaries, automate
corpus feeding, and perform other diagnostic operations related to DSPAM.
Some of these include dspam_train, dspam_stats, and dspam_dump.

1.1 INSTALLATION

IMPLEMENTATION OPTIONS

There are many different ways to deploy DSPAM onto an existing network. The
most popular approaches are:

1. As a delivery agent proxy

When your mail server gets ready to deliver mail to a user's mailbox it calls 
a delivery agent of some sort. On most UNIX systems, this is procmail, maildrop,
mail.local, or a similar tool. When used as a delivery proxy, the DSPAM agent
is called in place of your existing agent - or better put, it can masquerade
as the local delivery agent. DSPAM then processes the message and will call
the /real/ delivery agent to pass the good mail into the user's mailbox,
quarantining the bad mail. DSPAM can optionally tag and deliver both spam
and legitimate mail.

In the diagram below, MTA refers to Mail Transfer Agent, or your mail server
software: Postfix, Sendmail, Exim, etc. LDA refers to the Local Delivery
Agent: Procmail, Maildrop, etc..

BEFORE:

    [MTA] ---> [LDA] ---> (User's Mailbox)

AFTER:

    [MTA] ---> [DSPAM] ---> [LDA] ---> (User's Mailbox)
                        \
                         \--> [Quarantine]
           [End User] ------> [Web UI]

2. As a POP3 Proxy

If you don't want to tinker with your existing mail server setup, DSPAM can
be combined with one of a few open source programs designed to act as a POP3
proxy. This means spam is filtered whenever the user checks their mail,
rather than when it is delivered. The benefit to this is that you can set up
a small machine on your network that will connect to your existing mail server,
so no integration is needed. It also allows your users to arbitarily point their
mail client at it if they desire filtering. The drawback to this approach is
that the POP3 protocol has no way to tell the mail client that a message is
spam, and so the user will have to download the spam (tagged, of course).

BEFORE:

    [End User] ---> [POP3 Server]

AFTER:

    [End User] ---> [POP3 Proxy] <--> [DSPAM]
                     \
                      \--> [POP3 Server]

3. As an SMTP Relay

Newer versions of DSPAM have seen features that allow it to function more
easily as an SMTP relay. An SMTP relay sits in front of your existing mail
server (requiring no integration). To use an SMTP relay, the MX records for 
your domains are repointed to the relay machine running DSPAM. DSPAM then 
relays the good (and optionally bad) mail to the existing SMTP server. This
allows you to use DSPAM with even a Windows-based destination mail server
as no integration is necessary. See doc/relay.txt for one example of how to
do this with Postfix.

BEFORE:

  { Internet } ---> [Company Mail Server]

AFTER:

  { Internet } --->  [ Inbound SMTP Relay  ]  --->  [Company Mail Server]
                         ( MTA <> DSPAM )     SMTP 
                          \                    or
                           \--> [Quarantine]  LMTP
             [End User] ------> [Web UI]

UPGRADING DSPAM

   Please see the file UPGRADING

FRESH INSTALLATION

0. PREREQUISITES

   DSPAM can use one of many different backends to store its information, and
   you will need to decide on one and install the appropriate software before
   you can build DSPAM. The following storage backends are presently available: 
 
   Driver       Requirements
   -------------------------------------------------------------------------
 T mysql_drv:   MySQL client libraries      (and a server to connect to) 
 T pgsql_drv:   PostgreSQL client libraries (and a server to connect to)
   sqlite_drv:  SQLite v2.7.7 or above 
   sqlite3_drv: SQLite v3.x
*T hash_drv:    None (Self-Contained Hash-Based Driver)

   Legend:
    * Default storage driver
    T Thread-safe (Required for running DSPAM in server daemon mode)

   In general, MySQL is one of the faster solutions with a smaller storage 
   footprint, and is well suited for both small and large-scale implementations.

   The hash driver (inspired by Bill Yerazunis' CRM Sparse Spectra algorithm)
   is the fastest solution by far and requires no dependencies, supports
   an auto-extend feature to grow the file size as needed, and is very
   fast and compact. It does, however, lack some features (such as merged 
   groups support) and uses a lot of memory to mmap() users.

   Documentation for any additional setup of your selected storage driver can 
   be found in the doc/ directory. You'll need to follow any steps outlined in 
   the storage driver documentation before continuing.

   You can download MySQL from http://www.mysql.com.
   You can download PostgreSQL from http://www.postgresql.com.
   You can download SQLite from http://www.sqlite.org.

1. CONFIGURATION

   DSPAM uses autoconf, so configuration is fairly standardized with other
   UNIX-based software:

   ./configure [options]

   DSPAM supports the configuration options below. Generally, the default
   configuration is more than acceptable, so it's a good idea not to tweak too
   many settings unless you know what you are doing.

   PATH SWITCHES

     --prefix=DIR
     Specify an alternative root prefix for installation.  The default is
     /usr/local. This does not affect the location of dspam.conf (which 
     defaults to /usr/local/etc). Use --sysconfdir= for this.

     --sysconfdir=DIR
     Specify an alternative home for the dspam.conf file. The default is
     prefix/etc.

     --with-dspam-home=DIR
     Specify an alternative DSPAM home for installation. This can alternatively
     be changed in dspam.conf, but is convenient to do on the configure line.
     The default is $prefix/var/dspam, or /usr/local/var/dspam.

     --with-logdir=DIR
     Specify an alternative log directory. The default is $dspam_home/log. Do
     not set this to /var/log unless DSPAM will have permissions to write to 
     the directory.

   FILESYSTEM SCALE

     The default filesystem scale is "small-scale", and writes each user to
     its own directory in the top-level DSPAM home data directory.  
     The following two switches allow the scale to be changed to be more 
     suitable for larger installations.

     --enable-large-scale
     Switch for large-scale implementation.  User data will be stored as
     $HOME/data/u/s/user instead of $HOME/data/user

     --enable-domain-scale
     Switch for domain-scale implementation.  When used, DSPAM expects 
     username@domain to be passed in as the user id and user data will be 
     stored as $HOME/data/domain.com/user and $HOME/opt-in/domain/user.dspam
     instead of $HOME/data/user

   INTEGRATION SWITCHES

     --with-storage-driver=DRIVER[,DRIVER2[...,DRIVERN]]
     Specify your storage driver selection(s).  A storage driver is a driver
     written specifically for DSPAM to store tokens, signature data, and
     perform other proprietary operations.  The default driver is hash_drv.
     The following drivers have been provided:

     mysql_drv:   MySQL Drivers 
     pgsql_drv:   PostgreSQL Drivers
     sqlite_drv:  SQLite v2.x Drivers 
     sqlite3_drv: SQLite v3.x Drivers
     hash_drv:    Self-Contained Hash Database

     If you are a packager, or wish to have multiple drivers built for any
     reason, you may specify multiple drivers by separating them with commas.
     This will cause the storage driver specified in dspam.conf to be 
     dynamically loaded at runtime rather than statically linked. If you wish
     to build only one driver, but dynamically, then specify it twice as in
     --with-storage-driver=mysql_drv,mysql_drv.

     If you will be compiling DSPAM to operate as a server daemon or to deliver
     via SMTP/LMTP, you will need to use a thread-safe driver (outlined in the
     chart earlier in this document).

     You may also need to use some of the driver-specific configure flags
     (discussed in the DRIVER SPECIFIC CONFIGURATION OPTIONS section below).

     --disable-trusted-user-security
     Administrators who wish to disable trusted user security may do so by
     using this configure flag.  This will cause DSPAM to treat each user as
     if they were "trusted" which could allow them to potentially execute
     arbitrary commands on the server via DSPAM. Because of this, administrators
     should only use this option on either a closed server, or configure their
     DSPAM binary to be executable only by users who can be trusted.  This
     option SHOULD NOT be used as a solution to your MTA dropping privileges
     prior to calling DSPAM. Instead, see the TRUSTED SECURITY section of this
     document.

     --enable-homedir
     When enabled, instead of checking for $HOME/$USER/opt-in/
     $USER[.dspam|.nodspam], DSPAM will check for a .dspam|.nodspam file in the
     user's home directory. DSPAM will also store each user's data in ~/.dspam
     when this option is enabled. Because of this, DSPAM will automatically 
     install and run setuid root so that it can read each user's home directory.

     Note:

       This function is incompatible with most implementations of the Web UI, 
       since it requires access to read each user's home directory. Therefore, 
       only use this option if you will not be using the Web UI or plan on 
       doing something asinine like running it as root.

     --enable-daemon
     Builds DSPAM with support for daemon mode, and builds associated dspamc
     thin client. Pthreads is required to build for daemon mode and the
     storage driver used must be thread-safe.

   DRIVER SPECIFIC CONFIGURE SWITCHES

     Some storage drivers have their own custom configuration switches:

     mysql_drv:
       --with-mysql-includes=DIR
       Specify a path to the MySQL includes

       --with-mysql-libraries=DIR
       Specify a path to the MySQL libraries
       (Currently links to -lmysqlclient, also -lcrypto on some systems)

       --enable-virtual-users
       Tells DSPAM to create virtual user ids.  Use this if your users don't
       actually exist on the system (e.g. in /etc/passwd if using a password 
       file)

       --enable-preferences-extension
       MySQL supports the preferences extension, which stores user preferences
       in mysql instead of flat files (the built-in method)

       --disable-mysql4-initialization
       If you are compiling libdspam for use with a third party application,
       and the third party application makes its own calls to libmysqlclient,
       you should use this option to disable libdspam's initialization and
       cleanup of libmysqlclient, and allow the application to manage this.
       This option suppresses libdspam's calls to mysql_server_init and
       mysql_server_end.

       Note:

       Please see the file doc/mysql_drv.txt for more information
       about configuring the mysql_drv storage driver.

     pgsql_drv:
       --with-pgsql-includes=DIR
       Specify a path to the PgSQL includes

       --with-pgsql-libraries=DIR
       Specify a path to the PgSQL libraries
       (Currently links to -lpq, and netlibs on some systems)

       --enable-virtual-users
       Tells DSPAM to create virtual user ids.  Use this if your users don't
       actually exist on the system (e.g. in /etc/passwd if using a password 
       file)

       --enable-preferences-extension
       Postgres supports the preferences extension, which stores user 
       preferences in pgsql instead of flat files (the built-in method)

       Note:

       Please see the file doc/pgsql_drv.txt for more information about
       configuring the pgsql_drv storage driver.

     sqlite_drv:
     sqlite3_drv:
       --with-sqlite-includes=DIR
       Specify a path to the SQLite includes

       --with-sqlite-libraries=DIR
       Specify a path to the SQLite libraries

   DEBUGGING SWITCHES

     --enable-debug
     Turns on support for debugging output. This option allows you to turn on 
     debugging messages for all or some users by editing dspam.conf or setting
     --debug on the commandline. Enabling debug in configure only adds support 
     for debug to be compiled in, it must still be activated using one of the 
     options prescribed above. Debugging support itself doesn't use up very 
     many additional resources, so it should be safe to leave enabled on 
     non-enterprise class systems.

     --enable-verbose-debug
     Turns on extremely verbose debugging output. --enable-debug is implied.
     Never use this on production builds! 

     Note:

     When verbose debug is compiled in, DSPAM performs many additional
     mathematical calculations regardless of whether or not it's been
     activated. You shouldn't use --enable-verbose for production builds
     unless you have serious issues you can't resolve.

   FEATURE ACTIVATION

     --enable-clamav
     Enables support for Clam Antivirus. DSPAM can interface directly with 
     clamd to perform virus scanning and can be configured to react in 
     different ways to viruses. See dspam.conf for more information.

   ADDITIONAL CONFIGURATION OPTIONS

     The remainder of configuration options are located in dspam.conf, which
     is installed in sysconfdir (default: /usr/local/etc) upon a make install.
     It is generally a good idea to review dspam.conf and make any changes
     necessary prior to using DSPAM.

2. BUILDING AND INSTALLING

   After you have run configure with the correct options, build and install
   DSPAM by performing:

   make && make install

   Note: 

     If you are a developer wanting to link to the core engine of dspam,
     libdspam will be built during this process.  Please see the
     example.c file for examples of how to link to and use libdspam. Static
     and dynamic libraries are built in the .libs directory. Needed headers
     will be installed in $prefix$/include/dspam.

3. PERMISSIONS

   In the typical UNIX environment, you'll need to worry about the following
   permissions:

   The CGI User: This is the user your web server (most likely Apache) is
     running as. This is commonly 'nobody' or 'web'. You can find this in
     Apache's httpd.conf by searching for 'User'. The CGI user will need
     the ability to access the following components of DSPAM:
       - Ability to execute the dspam binary
       - Ability to read and write to dspam_home/data/
       - Trusted user permissions in dspam.conf ("Trust [username]")
       - The execution 'Group' used must match the group dspam is running as
         (this is typically 'mail', 'dspam', or similar)
     
   The MTA User: This is the user your mail server software is running as when
     it executes DSPAM. This is usually daemon, mail, exim, etc. This is 
     typically different from the user the MTA runs and polices itself as, to
     avoid security problems. Consult your MTA's documentation for more info.
     The MTA user will require:
       - The ability to execute the dspam binary
       - Trusted user permissions in dspam.conf ("Trust [username]")

   Systems Administrators: In order to perform administrative functions,
     systems administratiors will require:
       - The ability to execute dspam-related binaries
       - Trusted user permissions in dspam.conf ("Trust [username]")

   Note:
 
     If the MTA is communicating with DSPAM via LMTP (explained later), then
     execution permissions are not necessary

   Note about FreeBSD:

     FreeBSD's default MTA user is 'mailnull'
     FreeBSD's default delivery agent also changes its uid, and so in order
     to call it, dspam must be installed as setuid root to work on the 
     commandline properly. This is done automatically on install.


   Understanding Trusted User Security

   DSPAM has tighter security for untrusted users on the system to prevent
   them from touching other user's data or passing arbitrary commands to the
   delivery agent DSPAM calls. "Trusted User Security" is a simple system 
   whereby any unsafe functions are not available to a user calling dspam 
   unless they are within dspam.conf's trusted user list. 

   Local non-privileged users should be able to use DSPAM without any problems
   while remaining untrusted, as long as they behave. For example, an untrusted
   user cannot set their DSPAM username to any name other than their username.
   Untrusted users are also limited to the delivery options set by the
   system administrator, and cannot redirect how DSPAM delivers mail.

   A list of trusted users is maintained in dspam.conf. This file should
   include a list of trusted users who should be allowed to set the dspam user,
   passthru parameters, and other information that would be potentially 
   dangerous for a malicious user to be able to set.  You'll need to ensure 
   that your CGI user, MTA user, and system administrators are on the list.

4. MAIL SERVER INTEGRATION

   As previously mentioned, there are three popular ways to implement DSPAM:

   As a delivery proxy:
     The default approach integrates DSPAM directly with the mail server and 
     filters spam as mail comes in. Please see the appropriate instructions 
     in doc/ pertaining to your MTA.

   As a POP3 proxy:
     This alternative approach implements a POP3 proxy where users
     connect to the proxy to check their email, and email is filtered when
     being downloaded.  The POP3 proxy is a much easier approach, as it
     requires much less integration work with the mail server (and is ideal 
     for implementing DSPAM on Exchange, etcetera). Please see the file
     doc/pop3filter.txt.

   As an SMTP Relay:
     DSPAM can be configured as an SMTP relay, a.k.a appliance. You
     can set it up to sit in front of your real mail server and then point
     your MX records at it. DSPAM will then pass along the good mail to
     your real SMTP server. See doc/relay.txt for more information. The
     example provided uses Postfix and MySQL.

   Trusted users and the MTA

   If you are using an MTA that changes its userid to match the destination
   user before calling DSPAM, you won't be able to provide pass-thru 
   arguments to DSPAM (these are the commandline arguments that DSPAM in turn
   passed to the local delivery agent, in such a configuration). 
   You will need to pre-configure the "default" pass-thru arguments in DSPAM. 
   This can be done by declaring an untrusted delivery agent in dspam.conf.
   When DSPAM is called by an untrusted user, it will automatically force their
   DSPAM user id and passthru delivery agent arguments specified in dspam.conf.

   This information will override any passthru commandline parameters
   specified by the user. For example:

   UntrustedDeliveryAgent       "/bin/mail -d $u"

   The variable $u informs DSPAM that you would like the destination username
   to be used in the position $u is specified, so when DSPAM calls your LDA
   for user 'bob', it will call it with:

   /bin/mail -d bob

5. ALIASES

   There are essentially two different ways a user might train DSPAM. The first
   is by using the Web UI, which allows them to retrain via the "History"
   tab. This works quite well, as users must visit the Web UI occasionally
   to review their quarantine anyway (and reverse any false positives). We'll
   discuss this shortly in section 1.1.8.

   The more common approach to training, discussed here, is to allow users to
   simply forward their spam to an email address where DSPAM can analyze and
   learn it. DSPAM uses a signature-based system, where a serial number of
   sorts is appended to each email processed by DSPAM. DSPAM reads this serial
   number when the user forwards (or bounced) a message to what is called their
   "spam email address". The serial number points to temporary information
   stored on the server (for 14 days by default) containing all of the 
   information necessary for DSPAM to relearn the message. This is necessary
   in order to relearn the *exact* message DSPAM originally processed.

   Note:

     If you are using an IMAP based system, Web-based email, or other form of
     email management where the original messages are stored on the server in
     pristine format, you can turn this signature feature off by setting
     "TrainPristine on" in dspam.conf. DSPAM will then use the message itself
     that you provide it to train, which MUST be identical to the original
     message in order to retrain properly.

   Because DSPAM learns each user's specific email behavior, it's necessary
   to identify the user in order to program their specific filtering database.
   This can be done in one of three ways:

   The Simple Way:

     If you are using the MySQL or PgSQL storage drivers, the original
     numeric user id can be embedded in the signature, requiring only one
     central spam alias to be necessary for the entire system. To configure
     this, uncomment the appropriate UIDInSignature option in dspam.conf:

     # MySQLUIDInSignature    on
     # PgSQLUIDInSignature    on  

     Now all you'll need is a single system-wide alias, and DSPAM will train
     the appropriate user when it sees the signature. An example of an alias
     might look like:

     spam:"|/usr/local/bin/dspam --user root --class=spam --source=error"

     Similarly, you may also wish to have a false-positive alias for users who
     prefer to tag spam rather than quarantine it:

     notspam:"|/usr/local/bin/dspam --user root --class=innocent --source=error"

     Note:

     The 'root' user represents any active dspam user. It is necessary to 
     supply a username on the commandline or DSPAM will bail on
     an error, however the user will be changed internally once the signature
     is read.

   The Kind-of-Simple Way:

     If you're not using one of the above storage drivers, the next easiest
     way to configure aliases is to have DSPAM parse the 'To:' header of the
     message and use a catch-all subdomain to direct all mail into DSPAM for
     retraining. You can then instruct your users to email addresses like
     'spam-bob@relearn.domain.tld'. The ParseToHeaders option (available
     in dspam.conf) will parse the To: header of forwarded messages and
     set the username to either 'bob' or 'bob@relearn.domain.tld', depending 
     on how it is configured. DSPAM can also set the training mode to either
     "learn spam" or "learn notspam" depending on whether the user specified
     a spam- or notspam- address in the To: header.

     This is ideal if you don't want to set up a separate alias for each user 
     on your system (The Hard Way). If you're fortunate enough to have a
     mail server that can perform regular expression matching, you can set up
     your system without a subdomain, and just use addresses like 
     spam-bob@domain.tld. For the rest of us, it will be necessary to set up
     a subdomain catch-all directly into DSPAM. For example:

     @relearn.domain.tld	"|/usr/local/bin/dspam"

     Don't forget to set the appropriate ParseToHeaders and related options in
     dspam.conf as well. More specific instructions can be found in dspam.conf
     itself. In most cases, the following will suffice:

     ParseToHeaders on
     ChangeUserOnParse user
     ChangeModeOnParse on

   The Old Way (A.K.A. The Hard Way)

     If neither of the easy ways are possible, you're stuck with doing it
     the hard way. This means you'll need a separate spam alias (and notspam
     alias, if users are tagging mail) for each user. To do this, you will
     need to create an email address for each user, so that DSPAM can 
     analyze and learn for that specific user.  For example:

     spam-bob: "|/usr/local/bin/dspam --user bob --class=spam --source=error"

     You will end up having one alias per mail user on the system, two if you
     do not use DSPAM's CGI quarantine (an additional one using notspam-). Be 
     sure the aliases are unique and each username matches the name after the 
     --user flag.  A tool has been provided called dspam_genaliases.  This tool 
     will read the /etc/passwd file and write out a dspam aliases file that can 
     be included in your master aliases table.  

     To report spam, the user should be instructed to forward each spam to
     spam-user@yourhost

     It doesn't really matter what you name these aliases, so long as the flags
     being passed to dspam are correct for each user.  It might be a good idea
     to create an alias custom to your network, so that spammers don't forward
     spam into it.  For example, notspam-yourcompany-bob or something.  

   Note About Security:

     You might be wondering if a user can forward a spam to another user's
     address, or whether a spammer can forward a spam to another user's
     notspam address. The answer is "no". The key to all mail-based retraining
     is the signature embedded in each email. The signature is stored with
     each user's own user id, and so not only does the incoming message have
     to bear a valid signature, but it also has to be stored on the system with
     the correct user id. This prevents any kind of alias abuse.

6. NIGHTLY MAINTENANCE AND HOUSEKEEPING CRONS

   Non-SQL Based Nightly Purge

     If you are NOT running a SQL-based solution, then you should configure
     dspam_clean to run under cron nightly. This clean tool will read all 
     signature databases and purge signatures that are older than 14 days 
     (configurable), purge abandoned tokens, and remove unimportant tokens.  
     Without this tool, old signatures will continue to pile up. 
     Be sure the user running cleanup has full read/write permissions on the 
     DSPAM data files.

     0 0 * * * /usr/local/bin/dspam_clean [options]

     See the dspam_clean description for more information

   SQL-Based Nightly Purge

     SQL-Based solutions include a nightly SQL script to perform the same basic
     tasks as dspam_clean, and it does it much faster and with more finesse.
     You can find instructions about each driver's purge functions in
     the driver's README (doc/[driver].txt) for performing nightly
     maintenance. Most SQL drivers will include a purge script in the
     src/tools.[driver] directory. For example:

     0 0 * * * mysql --user=[user] --pass=[pass] [db] < /path/to/purge-4.1.sql

   Log Rotation

     The system log and user logs can fill up fairly quickly, when all that's
     really needed to generate graphs are the last two to three weeks of data. 
     You can configure a nightly log cleanup using dspam_logrotate:

     0 0 * * * dspam_logrotate -a 30 -d /usr/local/var/dspam/data

7. NOTIFICATIONS

   DSPAM is capable of sending three different notifications to users:

     - A "First Run" message sent to each user when they receive their first 
       message through DSPAM.

     - A "First Spam" message sent to each user when they receive their first
       spam

     - A "Quarantine Full" message sent to each user when their quarantine box
       is > 2MB in size.

   These notifications can be activated by copying the txt/ directory from the
   distribution into DSPAM's home (by default /usr/local/var/dspam).  You will
   want to modify these templates prior to installing them to reflect the 
   correct email addresses and URLs (look for 'configureme' and 'yourdomain').

   NOTE: The quarantine warning is reset when the user clicks 'Delete All', but
   is not reset if they use "Delete Selected".  If the user doesn't wish to
   receive reminders, they should use the "Delete Selected" function instead
   of "Delete All".

   You'll need to also set "Notifications" to "on" in dspam.conf.

8. THE WEB UI

   The Web UI (CGI client) can be run from any executable location on
   a web server, and detects its user's identity from the REMOTE_USER
   environment variable. This means you'll need to use HTTP password
   authentication to access the CGI (Any type of authentication will work,
   so long as Apache supports the module). This is also convenient in that you
   can set up authentication using almost any existing system you have.
   The only catch is that you'll need the usernames to match the actual 
   DSPAM usernames used the system. A copy of the shadow password file
   will suffice for most common installs.

   The accompanying files in the webui/ folder should be copied into your 
   document root and cgi-bin, as specified. 

     Note:

     Some authentication mechanisms are case insensitive and will
     authenticate the user regardless of the case they type it in.  DSPAM,
     on the other hand, is case sensitive and the case of the username used
     will need to match the case on the system.  If you suffer from this
     authentication problem, and are certain all of your users' usernames are
     in lowercase, you can add the following line of code to the CGI right
     after the call to &ReadParse...

     $ENV{'REMOTE_USER'} = lc($ENV{'REMOTE_USER'});

   The CGI will need to function in the same group as the dspam agent in order
   to work with the files in dspam_home.  The best way to do this is to create 
   a separate virtualhost specifically for the CGI and assign it to run in the 
   MTA group using Apache's suexec. If you are using procmail, additional 
   configuration may also be necessary (see below).  

   Note:

     Apache users do NOT take on the identity of the groups specified in 
     /etc/group so you will need to specifically assign the group in 
     httpd.conf.

   Note about Procmail:

      Because the DSPAM Web UI is a CGI script, DSPAM will not retain its 
      setuid privileges when called. If you are running procmail, this will 
      become a problem as procmail requires root privileges to deliver. The 
      easiest hack around this is to create a procmail.dspam binary and make it
      setuid root, then make it executable only by the mail group (or 
      whatever group DSPAM and the CGI run in).

   The DSPAM Web UI has a minimal configuration inside the configure.pl script. 
   You'll want to check and make sure all of the settings are correct. In
   most cases, the only that will be necessary to change are the large-scale
   or domain-scale flags.

   BEFORE PROCEEDING:
     Check and make sure (Again) that the CGI user from Apache's httpd.conf is
     added as a trusted user in dspam.conf.

   Default Preferences

   Now would be a good time to set the system's default preferences. This can 
   be done using the dspam_admin tool.  For example:

     dspam_admin ch pref default trainingMode TEFT
     dspam_admin ch pref default spamAction quarantine
     dspam_admin ch pref default spamSubject "[SPAM]"
     dspam_admin ch pref default enableWhitelist on
     dspam_admin ch pref showFactors off
 
   The default preferences are used for any users who have not yet set their
   own preferences. You can also control which preferences the user may
   override by changing the "AllowOverride" settings in dspam.conf.

   By default, the parameters specified on the commandline will be used (if
   any). If, however, a preference is found for the particular user those 
   preferences will override the commandline. 

   GD Graphing Library

   If you plan on leaving DSPAM's logging function enabled, and would like to
   produce pretty graphs for your users, the graph.cgi script requires the
   following be installed on your machine:

   - GD Graphics Library (http://www.boutell.com/gd/)
     Compile with png support

   - The following PERL modules:
     (http://www.perl.com/CPAN/modules/by-module/GD/)

     . GD
     . GD-Graph3d
     . GDGraph
     . GDTextUtil
     . CGI

     Typically this can be accomplished on the commandline:

     perl -MCPAN -e 'install GD::Graph3d'

  Configuring Administrators

  Once you've configured the Web UI, you'll want to edit the 'admins' file to
  contain a list of users who are permitted to use the administration suite.

  Opt-In/Out

  If you would like your users to be able to opt in/out of DSPAM filtering,
  add the correct option to the nav_preferences.html template, depending on
  your configuration (for example, if you have an opt-in system, you'll want to
  add the opt-in option). Note: This currently only works with the preferences
  extension, and not drop files.

<INPUT TYPE=CHECKBOX NAME=optIn $C_OPTIN$>
Opt into DSPAM filtering

<INPUT TYPE=CHECKBOX NAME=optOut $C_OPTOUT$>
Opt out of DSPAM filtering

1.2 TESTING

  If you've installed from an RPM, there's a good chance that the packager
  went to the trouble of testing already. If you're building from sources,
  however, you'll need to find a way to ensure your configuration isn't broken.

  Most software packages are supplied with a test suite to determine if the
  software is functioning properly.  Since DSPAM's correct function relies 
  primarily on having the correct permissions and mail server configuration,
  a test script fails to provide the level of testing required for such a
  package.  The following exercise has been provided to test dspam's correct
  functioning on your system. This exercise does not test the Web UI, but only
  the core dspam agent.
  
  Before running the test, you should have completed section 1.1's instructions
  for compiling and installing dspam as well as configured your mail server
  to support dspam.

  1. Create a new user account on your system.  It is important that this be a 
  new account to prevent any unrelated email from being delivered during 
  testing.  Be sure to configure a spam alias for the test account.

  2. Send a short (10 words or less) email to the account, and pick it up 
  using your favorite mail client.  

  3. Run dspam_stats [username] on the server.  You should see a value of 1 
  for "TI" or "Total Innocent" as shown below:

  dspam-test            0 TP       1 TN       0 FN       0 FP

  If you receive an error such as "unable to open /usr/local/var/dspam... for
  reading", then the dspam agent is not configured correctly.  The problem
  could exist in either your mail server configuration or one or more of the
  permissions on the directory or agent.  Check your configuration and
  permissions, and repeat this step until the correct results are experienced.

  4. Run dspam_dump [username] to get a complete list of tokens and their 
  statistics.  Each token should have an I: (innocent) hit count of 1. The 
  tokens will be represented as 64-bit values, for example:

3126549390380922317              S:    0  I:    1  LH: Mon Aug  4 11:40:12 2003
13884833415944681423             S:    0  I:    1  LH: Mon Aug  4 11:40:12 2003
14519792632472852948             S:    0  I:    1  LH: Mon Aug  4 11:40:12 2003
8851970219880318167              S:    0  I:    1  LH: Mon Aug  4 11:40:12 2003

  To view statistics for a particular token, run dspam_dump [username] [token]
  where token is the plain-text token value.  For example:

  % dspam_dump bill FREE
  7717766825815048192  S: 00265  I: 00068  P: 0.7358

  5. Forward the test message to the spam alias you've created for the test 
  account.  Provide enough time for the message to have processed.

  6. Run dspam_stats [username] on the server again.  Now, the value for TN 
  should be zero and the value for FN (false negatives) should be 1 as shown
  below:

dspam-test            0 TP       0 TN       1 FN       0 FP

  If this is not the case, check the group permissions of the dspam agent as
  well as the permissions your MTA uses when piping to aliases.
  
  7. Run dspam_dump [username] again.  make sure that _EVERY_ token now has an 
  I: of zero and a S: of 1:

3126549390380922317              S:    1  I:    0  LH: Mon Aug  4 11:44:29 2003
13884833415944681423             S:    1  I:    0  LH: Mon Aug  4 11:44:29 2003
14519792632472852948             S:    1  I:    0  LH: Mon Aug  4 11:44:29 2003
8851970219880318167              S:    1  I:    0  LH: Mon Aug  4 11:44:29 2003

  If you have some tokens that do not have an S: of 1 or an I: of 0, the dspam
  signature was not found on the email, and this could be due to a lot of
  things.

1.3 TROUBLESHOOTING

    Problem: No files are being created in the user directory
   Solution: Check the directory permissions of the directory.  The user 
             directory must be writable by the user the dspam agent is running
             as as well as the CGI user.

    Problem: False positives are never being delivered
   Solution: Your CGI most likely doesn't have the privileges required by
             the LDA to deliver the messages.  Make sure the CGI user is in
             the correct group.  Also consider setting the dspam agent to
             setuid or setgid with the correct permissions.

    Problem: My database is getting huge!
   Solution: DSPAM's default training mode is TEFT. On top of this, the
             purging defaults are very lax. You might consider switching to
             TOE (Train-on-Error) mode training if you require a minimal
             database. If you are willing to sacrifice accuracy for disk space,
             disabling the 'chain' tokenizer from dspam.conf will prevent
             the use of multi-word (chained) tokens, which will also cut your
             database size considerably. You may also consider more frequent
             calls to dspam_clean -p to purge neutral data, which comprises a
             majority of most databases.

  For more help, please see the DSPAM FAQ at http://dspam.nuclearelephant.com.

1.4 DSPAM TOOLS

  A few useful tools have been provided to make DSPAM management a bit easier. 
  These tools include:

  dspam_admin - A tool used to perform specific administrative functions. These
    functions are usually included as part of an extensions package (such as
    the preferences extension). Available functions are listed in the tool's
    usage output.

  dspam_train - Used to train and test a corpus of ham and spam (in maildir
    format). 
    Syntax: dspam_train [username] [spam_dir] [nonspam_dir]
    where username is the username of the user to apply the training to, and
    the two dirs represent directories containing messages in individual
    files (e.g. maildir/corpus format). dspam_train can be used on an existing
    user's database, to further improve accuracy, or to train from scratch.
    it also provides a solid test jig for testing the efficiency and accuracy
    of a test corpus against the filter. 
    NOTE: dspam_train will automatically balance training of the corpus to
          ensure both spam and nonspam are trained based on the ratio of 
          spam/nonspam. this means if you have twice as much spam as nonspam,
          two spam will be trained for every nonspam.
    
  dspam_dump - Dumps a DSPAM dictionary. This can be used to view the 
    entire contents of a user's dictionary, or used in combination 
    with grep to view a subset of data.  Syntax: dspam_dump [username] [token] 
    where username is the DSPAM user's username.  If a token is specified,
    statistics only for that token will be printed.

  dspam_clean - Performs nightly housecleaning by deleting old or useless
    data from user data.  dspam_clean performs the following operations:

    1. Using the -s flag, dspam_clean will continue to perform stale signature
     purging.  If an age is specified, for example -s14, the age defined as the
     default will be overridden.  Specifying an age of 0 will delete all
     signatures for the users processed.
                                                                                
    2. Using the -p flag, dspam_clean will delete all tokens from a user's 
     database whose probability is between 0.35 and 0.65 (fairly neutral, 
     useless tokens) that fall beyond the default age.  If an age is specified,
     for example -p30, the age defined as the default will be overridden.  It 
     is a good idea to use this type of clean with an age of 0 on users after
     a lot of corpus training.
                                                                                
    3. Using the -u flag, dspam_clean will delete all unused tokens from a 
     user's database.  There are four different types of unused tokens:
                                                                                
     - Tokens which have not been used for a long time
     - Tokens which have a total hit count below 5
     - Tokens which have only one spam hit
     - Tokens which have only one innocent hit
                                                                                
   Ages may be overridden by specifying a format such as -u30,15,10,10
   where each number represents the respective age.  Specifying an age of
   zero will delete all unused tokens in the category. Defaults are set in
   dspam.conf.
                                                                                
   Optionally, usernames may be specified to override the default behavior of
   processing all users.

   Examples:

   Process all users on the system using all clean operations:
     dspam_clean -s -p15 -u90,30,15,15

   Delete all of user 'dick' and 'jane's signatures:
     dspam_clean -s0 dick jane

   Perform a post-corpus training clean on user 'spot':
     dspam_clean -p0 -u0,0,0,0 spot

   Run dspam_clean with all default options, all clean modes enabled, on all
   users on the system:
     dspam_clean -s -p -u

  NOTE: You may wish to only run certain cleaning modes depending on the type 
  of storage driver you are using.  For example, the MySQL storage driver
  includes a script which performs signature and unused token operations, 
  leaving only probability operations as useful.  If you are using a SQL-based
  storage driver, it is strongly recommended that you use the maintenance 
  scripts wherever possible for optimum efficiency.

  dspam_stats - Displays the spam statistics for one or all users on the system.
    Syntax: dspam_stats [username].  If no username is provided, all users 
    will be displayed.  Displays TP (true positives), TN (true negatives),
    FN (false negatives), and FP (false positives).

  dspam_genaliases - Reads the /etc/passwd file and outputs a dspam aliases
    table which can be included in the master aliases table.  You may try
    Art Sackett's generate_dspam_aliases tool at 
    http://www.artsackett.com/freebies/generate_dspam_aliases/ if you need
    some better functionality.  This will eventually be merged in as a
    replacement for the existing tool.
 
  dspam_merge - Merges multiple users' dictionaries together into one user's
    dictionary (does not affect the merge users).  This can be used to create
    a seeded dictionary for a new user, or to copy a single user's dictionary
    to a new file.  This is great for building global dictionaries, but
    crunches a lot of time and disk.

1.5 AGENT COMMANDLINE ARGUMENTS

  The DSPAM agent (dspam) recognizes the following commandline arguments:

  --user [user1 user2 ... userN]
  Specifies the destination user(s) of the incoming message.  DSPAM then 
  processes the message once for each user individually.  If the message is to
  be delivered, the $u (or %u) parameters of the arguments string will be
  interpolated for the current user being processed.

  --class=[spam|innocent]
  Tells DSPAM that the message being presented has already been classified by
  the user.  This flag should be used when a misclassification has occurred, 
  when the user is corpus-feeding a message, or an inoculation is being 
  presented.  This flag must be used in conjunction with the --source flag.
  Providing no classification invokes the SOP of DSPAM, which is to determine
  the message's nature on its own.

  --source=[error|corpus|inoculation]
  Wherever --class is used, the source of the user-provided
  classification must also be provided.  The source is very important and
  dramatically affects DSPAM's training behavior:

    error: The message being presented was a message previously misclassified
           by DSPAM.  When 'error' is provided as a source, DSPAM requires that
           the DSPAM signature be present in the message, and will use the
           signature to recall the original training metadata.  If the signature
           is not present, the message will be rejected.  In this source mode,
           DSPAM will also decrement each token's previous classification's
           count as well as the user totals.

           You should use error only when DSPAM has made an error in 
           classifying the message, and should present the modified version of
           the message with the DSPAM signature when doing so.

   corpus: The message being presented is from a mail corpus, and should be
           trained as a new message, rather than re-trained based on a
           signature.  The message's full headers and body will be analyzed and
           the correct classification will be incremented, without its
           opposite being decremented.

           You should use corpus only when feeding messages in from corpus, not
           for correcting errors.

   inoculation: The message being presented is in pristine form, and should
                be trained as an inoculation.  Inoculations are a more 
                intense mode of training designed to cause DSPAM to 
                train the user's metadata repeatedly on previously unknown
                tokens, in an attepmt to vaccinate the user from future
                messages similar to the one being presented.

                You should use inoculation only on honeypots and the like.

  --deliver=[innocent,spam]
  Tells DSPAM to deliver the message if its result falls within the criteria
  specified.  For example, --deliver=innocent will cause DSPAM to only 
  deliver the message if it classifies as innocent.  Providing
  --deliver=innocent,spam will cause DSPAM to deliver the message regardless
  of its classification.  This flag provides a significant amount of 
  flexibility for nonstandard implementations, where false positives may not
  be delivered but spam is, and etcetera.
  
  --stdout
  If the message is indeed deemed "deliverable" by the --deliver flag, this
  flag will cause DSPAM to deliver the message to stdout, rather than 
  the configured delivery agent.

  --process
  Tells DSPAM to process the message.  This is the default behavior, and the
  flag is implied unless --classify is used - but is a good idea to use to 
  avoid ambiguity.

  --classify
  Tells DSPAM only to classify the message, and not make any writes to the
  user's metadata or attempt to deliver/quarantine the message.  

  NOTE: The output of the classification is specific to the user, not including
        the output of any groups they might be affiliated with, so it is 
        entirely possible that the message would be caught as spam by the group,
        even if it didn't appear in the classification.  If you want to get
        the classification for the GROUP, use the group name as the user
        instead of an individual.

  --signature=[signature]
  For some implementations, the admin may wish to pass the signature in
  via commandline instead of allowing DSPAM to find it on its own. This is
  especially useful when front-ending the agent with other tools. Using this
  option will set the active signature and will also forego reading of stdin.
  
  --mode=[toe|tum|teft|notrain|unlearn]
  Configures the training mode to be used for this process:

    teft: Train-Everything.  Trains on all messages processed.  This is
          a very thorough training approach and should be considered the 
          standard training approach for most users.  TEFT may, however,
          prove too volatile on installations with extremely high per-user
          traffic, or prove not very scalable on systems with extremely large
          user-bases.  In the event that TEFT is proving ineffective, one of
          the other modes is recommended.

          NOTE: Until a user reaches 100 innocent messages in their
                metadata, train-on-error will also be teft-based, even if
                otherwise specified on the commandline.

     toe: Train-on-Error.  Trains only on a classification error, once the
          user's metadata has matured to 2500 innocent messages.  This
          training mode is much less resource intensive, as only occasional
          metadata writes are necessary.  It is also far less volatile than
          the TEFT mode of training.  One drawback, however, is that TOE only
          learns when DSPAM has made a mistake - which means the data is
          sometimes too static, and unable to "ease into" a different type of
          behavior.

     tum: Train-until-Mature.  This training mode is a hybrid between the other
          two training modes and provides a great balance between volatility
          and static metadata.  TuM will train on a per-token basis only
          tokens which have had fewer than 50 "hits" on them, unless an error
          is being retrained in which case all tokens are trained.  This
          training mode provides a solid core of stable tokens to keep
          accuracy consistent, but also allows for dynamic adaptation to any
          new types of email behavior a user might be experiencing. It is a
          balance of resources as well, as only less-than-mature tokens are
          written to the database. NOTE: You should corpus train before
          using tum.

 notrain: No training.  Do not train the user's data, and do not keep totals.
          This should only be used in cases where you want to process mail for
          a particular user (based on a group, for example), but don't want
          the user to accumulate any learning data.

 unlearn: Unlearn original training. Use this if you wish to unlearn a
          previously learned message. Be sure to specify --source=error and
          --class to whatever the original classification the message was
          learned under. If not using TrainPristine, this will require the
          original signature from training.
 
    RECOMMENDATIONS:
      In general, it is recommended that users begin with TEFT.  If a user
      is experiencing between a 75-85% spam ratio, they may benefit from
      Train-on-Mature mode.  If a user is experiencing over 90% spam, then
      Train-on-Error mode should make a noticeable improvement in accuracy.
      It eventually boils down to what works best for your users.  There is
      no reason a system could not be configured (with a script) to
      analyze a user's *.stats file and determine the best training mode
      for that user.

  --feature=[noise,whitelist,tb=N]
  Specifies the features that should be activated for this filter instance.
  The following features may be used individually or combined using a comma
  as a delimiter:

     noise:  Bayesian Noise Reduction (BNR).  Bayesian Noise Reduction kicks
             in at 2500 innocent messages and provides an advanced progressive
             noise logic to reduce Bayesian Noise (wordlist attacks) in
             spams.  See http://bnr.nuclearelephant.com for more information.
             BNR is not for everyone, and so users should try it out after 
             they've trained to see if it helps improve accuracy.

      tb=N:  Sets the training loop buffering level.
             Training loop buffering is the amount of statistical sedation
             performed to water down statistics and avoid false positives 
             during the user's training loop.  The training 
             buffer sets the buffer sensitivity, and should be a number
             between 0 (no buffering whatsoever) to 10 (heavy buffering).  The 
             default is 5, half of what previous versions of DSPAM used.  
             To avoid dulling down statistics at all during the training loop, 
             set this to 0. This feature should be disabled if you're not
             paranoid about false positives, as it does increase the number
             of spam misses significantly during training.

 whitelist:  Automatic whitelisting.  DSPAM will keep track of the entire
             "From:" line for each message received per user, and automatically
             whitelist messages from senders with more than 10 innocent
             messages and zero spams.  Once the user reports a spam from the
             sender, automatic whitelisting will automatically be deactivated
             for that sender.  Since DSPAM uses the entire "From:" line, and
             not just the sender's email address, automatic whitelisting is
             a very safe approach to improving accuracy during initial training.
  
   NOTE: None of the present features are necessary when the source is "error",
         because the original training data is used from the signature to 
         retrain, instantiating whatever features (such as whitelisting) were
         active at the time of the initial classification.  Since BNR is only 
         necessary when a message is being classified, the
         --feature flag can be safely omitted from error source calls.

  --daemon
  Puts DSPAM in daemon mode; e.g. DSPAM acts like a server when started with
  this parameter. See section 2.3 for more information about daemon mode.

2.0 LINKING WITH LIBDSPAM

  Developers are able to link to the DSPAM core engine (libdspam) to provide 
  "drop-in" spam-filtering for their applications.  Examples of the libdspam
   API can be found in the example.c file included with this distribution.

  <COMMERCIAL LICENSING>

  IF YOUR PROJECT USES THE LIBDSPAM API, A GPL-COMPATIBLE OPEN SOURCE LICENSE
  IS REQUIRED IN ORDER TO REDISTRIBUTE. IF YOU ARE DEVELOPING A CLOSED-SOURCE 
  APPLICATION OR APPLICATION THAT DOES NOT CONFORM TO GPL STANDARD, YOU MAY 
  NOT REDISTRIBUTE ANY APPLICATIONS USING LIBDSPAM WITHOUT A COMMERCIAL 
  LICENSE.

  COMMERCIAL LICENSING BENEFITS:
  - PRIORITY DEVELOPER SUPPORT
  - 1-YEAR, 2-YEAR, AND PERPETUAL LICENSING AVAILABLE
  - NON-GPL REDISTRIBUTION PRIVILEGES
  - BUG AND FEATURE REQUEST PRIORITY

  Please contact the author at jonathan@nuclearelephant.com for information 
  about commercial licensing. 

  </COMMERCIAL LICENSING>

  To link to libdspam, follow the instructions for compiling and installing 
  DSPAM. When compiled, the libdspam static and shared libraries are also 
  built. This library contains all the functions necessary to use dspam's 
  filtering in your application. 

  Your application will also need to link to the correct storage driver
  libraries. If you are using libdspam in a multithreaded application, you
  will need to either use a thread-safe storage driver or control access to
  libdspam using a mutex lock.

  If you are using libdspam in a multithreaded environment, each thread will
  require its own DSPAM context. Fortunately, you can attach the same
  database handle to each context using dspam_attach(). See the man page for
  more information.

  To build with the dspam API, you will also need the header files from
  the distribution.  You can copy these to /usr/include/dspam for ease of
  use, and then use -I/usr/include/dspam

  Please see example.c for API examples.

  If you are interested in linking libdspam with your project and have 
  questions or concerns, please contact the dspam-dev mailing list.

2.1 CONFIGURING GROUPS

  Groups enable a group of users to share information.  The following
  group types are supported:

  SHARED
  Enables users with similar email behavior to share the same dictionary 
  while still maintaining a private quarantine box.  The benefits of this
  type of group are faster learning, and sharing a single spam alias.  Shared
  groups can have both positive and negative effects on accuracy.  If a shared
  group consists of users with similar, predictable email behavior, the users 
  in the group can benefit from a larger dictionary of spam and faster 
  learning (especially for newcomers in the group).  If a group consists of 
  users with different email behavior, however, the users in the group will 
  experience poor spam filtering and a higher number of false positives.

  NOTE
    The SQL-based storage drivers support shared groups, but has one caveat:
    If you are NOT enabling "virtual users" support, you will need to create
    an actual user on your system named after each group you create.

  On top of shared group support, a shared group can also be made to be
  'managed'.  Using the group type 'SHARED,MANAGED' will cause the group to
  share a single quarantine mailbox which could be managed by the group's
  administrator.  This would enable one individual to monitor quarantine for
  the entire group, however personal emails marked as false positives could
  potentially be viewed as well.  For this reason, managed groups should only
  be used when this is not an issue.

  INOCULATION
  An inoculation group allows users to maintain their own private dictionaries
  with their own spam alias, but all members of the group will inoculate other
  members with spams they manually forward into their alias.  This allows 
  users to report spams to one another and maintain their own private
  dictionary.  Another advantage to this is that users do not necessarily have
  to share the same email behavior.  

  NOTE: Users should only be added to an inoculation group after their initial
        learning period, to avoid potential false positives due to lack of data.

  To create groups, you'll want to create a file with the filename 'group' 
  located in the DSPAM user directory.  The default is
  /usr/local/var/dspam/group. The format of the file should look like this:

  group1:shared:user1,user2,user3
  group2:inoculation:user4,user5,user6

  A user can be a member of multiple inoculation groups, but a user cannot be
  a member of both an inoculation group and a shared group.

  DSPAM will read this file upon startup and determine if the user fits into
  any particular group.  
  
  Use the dspam_stats tool to keep an eye on the effectiveness of shared groups.
  If a shared group experiences poor performance, find the users whose email 
  behavior is inconsistent with that of the group and remove them from the 
  group.

  CLASSIFICATION
  Classification groups allow a group of users to network their results
  together.  If DSPAM is uncertain of whether a message is spam or nonspam for
  a group member, all other members of the group are queried.  If another
  member believes the message to be spam, it will be marked as spam.

  A user can simultaneously be a member of a classification and inoculation
  group, but a user cannot be a member of both a classification group and a
  shared group.

  VERSATILE LANGUAGE INOCULATION MESSAGES

  A new Internet-Draft has been released to the public:

    http://www.ietf.org/internet-drafts/draft-spamfilt-inoculation-00.txt

  To create a message format standard for sending inoculation data via email.
  This will allow users on different servers, and even using different 
  anti-spam tools to share inoculation information with one-another.

  DSPAM presently implements support for this message standard with the 
  following limitations:

  - Only inbound inoculation messages are supported.  DSPAM does not yet send
    out inoculations using this message format.  This should not be confused
    with local inoculation, which *is* supported.
  
  - The message/inoculation format is the only inoculation type presently
    supported.  text/inoculation and multipart/inoculation coming soon.

  - The only supported authentication mechanism is presently md5 verification
    codes/checksums.

  Any unsupported inoculations will simply be dropped.

  A list of identifies and authentication information can be set up in the file
  [username].inoc or in the user's home directory in a .inoc file if
  homedir-dotfiles is enabled.  The format of this file is:

  sender1:shared secret
  sender2:shared secret

  Each sender should specify the correct sender id when sending an 
  inoculation, and should generate their checksum based on the shared secret
  established between both parties.

  GLOBAL GROUPS

  Global groups allows DSPAM to provide a "SpamAssassin type out-of-the-box
  filtering" for all new users until they have built their own useful
  dictionaries.  to create a global classification group, add something like
  this to $HOME/group:

  groupname:classification:*globaluser

  This will automatically add globaluser as a classification peer to all users.
  Any user who has less than 1000 innocent messages or 250 spam messages in
  their corpus, or whose filter is uncertain about a particular message will
  consult the global dictionary for an answer.

  Global groups will need to be trained using corpus or other means, or by
  using the dspam_merge tool.  the global user (in this case 'globaluser') is
  treated just as any other user on the system.

  NOTE: Be sure and set your global user's preferences so that trainingMode
        is set to TOE. This will prevent the purge tools you use from
        purging them empty in 90 days.

  MERGED GROUPS

  Merged groups are similar to global groups in that the entire system uses
  a single global user as a parent.  What's different is that the global
  group is merged with the individual user's training data at run-time,
  instead of switching between the two.  This allows the global group to be
  treated like a base dataset for all users, and provides for quicker
  learning and correction than the previous approach.  It is recommended 
  merged groups are only used with TOE-mode training so that only corrective 
  data is stored, but systems with ample amounts of disk may wish to run in
  TUM mode to learn the user's behavior dynamically.

  The group's data is merged with the user's data in real-time, so if you have:

  Group: Viagra = 10 Spam Hits, 0 Innocent Hits
   User: Viagra = 5 Spam Hits, 15 Innocent Hits

  Then the token is loaded as: 15 Spam Hits, 15 Innocent Hits = 0.50 (50%)

  No data is written to the group by DSPAM; only the user's data. This then
  offsets the group's data without affecting other users. Because of the way
  this data is merged, it's not recommended that you update the merged group
  with more than a handful of messages periodically, as it affects how all
  stats are defined for each user.

  To set up a merged group, use something like this in your group file:

  groupname:merged:*
  groupname:merged:user1,user2,userN

  groupname represents the name of the global user to merge with all members of
  the group.

  NOTE: Merged Groups are great for providing out-of-the-box adaptive filtering,
        but allowing users to build their own data from scratch will still 
        result in the best possible accuracy in the longrun.

  NOTE: Be sure and set your global user's preferences so that trainingMode
        is set to TOE. This will prevent the purge tools you use from
        purging them empty in 90 days.


  IMPORTANT!

  If you are running dspam_clean, be sure to set a preference for your merged
  group users where trainingMode = TOE. This will cause dspam_clean to skip
  the purging of unused tokens from the global databases (which could wipe
  out your entire merged group user's dataset, since it's old).

2.2 EXTERNAL INOCULATION THEORY

  Bill Yerazunis recently expressed his theory of inoculation on an anti-spam
  development list, using the term "vaccination":

  "Part of the problem is that spam isn't stationary, it evolves. That 
   pesky .1% error rate is in some part due to the base mutation rate of spam 
   itself.  Maybe the answer is "vaccination".  Vaccination is using _one_ 
   person's misery be used to generate some protective agent that protects the 
   rest of the population; only the first person to get the spam actually has 
   to read it. 

   My expectation is this: say you have ten friends, and you all agree to share 
   your training errors.  Each of you will (statistically) expect to be the 
   first to see a new mutation of spam about 9% of the time; the other ten 
   friends in this group will have their bayesian filter trained preemptively 
   to prevent this.  Net result: you get a tenfold decrease in error rate - 
   down to 99.99% accuracy.  With a hundred such (trusted) friends, you may be 
   down to 99.999% accuracy."

   DSPAM has taken this concept and rolled it into support for what we call
   "inoculation groups" providing the exact functionality Bill describes.  This
   could be considered an "internal inoculation" practice.

   On top of this, DSPAM has been designed to support external inoculation as 
   a complement to internal inoculation.  This is where instead of your internal
   circle of friends inoculate you, you rely on external elements - namely
   spammers themselves - to inoculate you.

   The theory behind external inoculation is this: why put _anyone_ through
   the misery of being the first to receive a new spam when you can have
   the spammers themselves send it directly to you.  On top of this,
   external inoculation can be combined with internal inoculation by taking
   the spam you received externally and inoculating your friends with it
   internally.

   Inoculation is a little different from learning, as inoculation causes
   tokens to be given additional hit counts in an attempt to learn from a
   single email.  As a result, any form of inoculation should _only_ be
   attempted after an initial learning phase (perhaps when your filtering
   accuracy exceeds 99.0%).  DSPAM inoculates like this:

   1. Every token that doesn't already exist in the database, or have fewer
      than two hits will be hit five times.

   2. All other tokens are hit twice.

   External inoculation is accomplished by creating a covert, external alias
   that is configured to automatically inoculate your dictionary from any
   messages it receives.  The covert alias can then be published onto a series
   of public newsgroups and websites where it is sure to be harvested by
   a spammer's tools.  One could even pro-actively subscribe one's self to
   several different opt-in spam lists, etcetera.

   The first step is to configure an alias.  To do this you would use something
   like:

   bob_c:	"|/path/to/dspam --process --class=spam --source=inoculation --user bob"

   The 'C' in bob is for 'Covert'.  We must use a covert alias because if we
   use something obvious like 'bob-spam', harvester tools will automatically
   strip the -spam off and spam your real account.

   Once the alias is set up, make sure this alias gets out only on lists where
   harvesters will grab it, and nobody will send legitimate email to it.  
   It may even be a good idea to put it at the bottom of your tagline in all
   your publicly archived emails, something like...

   Spammers, send me mail here: bob_c@yourdomain.com

   Finally, you can multiply the effects of this by sharing an inoculation
   group with your friends.  If all of your friends have a public covert
   alias, then you will all be able to inoculate eachother should one of you
   receive a spam to the account.  What a great way to train your filter!

   On top of this, should external inoculation become commonplace to the
   point where harvesters are picking up an equal amount of them as legitimate
   email addresses, spammers will start to realize that harvesters are just
   plain too dumb to tell the difference (the spammers themselves couldn't tell
   if mine was or not).  This could, best case scenario, put an end to
   harvester bots, making them obsolete as counter-productive tools.

2.3 CLIENT/SERVER MODE

  DSPAM supports two different modes of operation.  In standard operating
  mode, the DSPAM agent is called by the MTA (or proxy) and each agent process 
  performs independently, establishing its own connection to a database and 
  performs delivery on its own. The second operating mode, client/server mode, 
  allows the DSPAM agent to act more like a thin client, connecting to the
  DSPAM server process which then does all the work of analyzing and delivering
  or quarantining the message. The advantages to using DSPAM in client/server 
  mode are:

  - Maintaining a set of stateful database connections (within the server),
    which should enhance performance on some systems by eliminating the need
    to establish a new database connection for every message processed.

  - Providing a central point of processing. Having one server perform all 
    processing and delivery, while having multiple thin clients on your mail 
    servers may be more desirable than having multiple agents performing 
    processing and delivery on all your servers.

  - The DSPAM server speaks LMTP, which some implementations may be able to
    take advantage of, eliminating the need for the DSPAM client all together.

  - Having a single multithreaded daemon should use less memory and other
    resources than having independently operating clients.

  If you've already got DSPAM set up, client/server mode won't require any
  changes to your mail server's configuration - it's completely transparent.

  The DSPAM agent can be compiled with client/server support by configuring
  with --enable-daemon. You will need to use a multithread-safe storage driver
  (presently mysql_drv and pgsql_drv are supported). Once you have compiled
  with daemon support, you'll need to modify your dspam.conf to provide the 
  settings necessary for client/server mode:

	ServerPort             24

  The port to listen on. The default is 24, the LMTP port.

	ServerQueueSize        32

  The maximum number of connections which may remain backlogged before they 
  are accepted.

	ServerPass.Relay1      "secret"
	ServerPass.Relay2      "password"

  Each client server allowed to connect should have its own password. They
  can be defined here.

  The DSPAM server can listen on either a network socket or a local unix
  domain socket. If you're running the client and server on the same machine,
  a domain socket should be used as it eliminates additional overhead. To use
  a domain socket, you'll also need to add the following option:

	ServerDomainSocketPath  "/tmp/dspam.sock"

  Once you've configured the server config, you'll want to set the client
  configuration on all client machines. If you are using network sockets,
  set the following to appropriate values:

	ClientHost     127.0.0.1
	ClientPort     24

  Or if using a domain socket:

        ClientHost     /tmp/dspam.sock

  In both cases, you'll need to set the client's authentication ident:

	ClientIdent    "secret@Relay1"

  Now you're ready to go. To start the DSPAM server, run:

	dspam --daemon &

  Or alternatively, if you have debugging enabled:

	dspam --debug --daemon &

  The DSPAM agent can then be called the same as if you were running in
  standard (non-client/server) mode and adding --client to the set of
  parameters. Running dspam without --client specified will cause DSPAM to
  revert to its normal non-daemon behavior and establish database connections
  on its own. The client settings will be loaded from dspam.conf, and the
  agent will act as a thin client instead. For example:

	dspam --client --user dick jane --deliver=innocent -d %u

  Alternatively, if you'd like to use a thinner client, dspamc is identical
  to the dspam binary in behavior, but has been stripped down to only include
  the lightweight client.

	dspamc --client --user dick jane --deliver=innocent -d %u

  The conversation that takes place between the client/server is LMTP-based,
  and will look like this:

SERVER> 220 DSPAM DLMTP 3.4.0 Authentication Required
CLIENT> LHLO Relay1
SERVER> 250-PIPELINING
SERVER> 250-ENHANCEDSTATUSCODES
SERVER> 250-DSPAMPROCESSMODE
SERVER> 250 SIZE
CLIENT> MAIL FROM: <secret@Relay1> DSPAMPROCESSMODE="--deliver=innocent -d %u"
SERVER> 250 2.1.0 OK
CLIENT> RCPT TO: dick
SERVER> 250 2.1.5 OK
CLIENT> RCPT TO: jane
SERVER: 250 2.1.5 OK
CLIENT> DATA
SERVER> 354 Enter mail, end with "." on a line by itself
CLIENT> Subject: Cheap Viagra!
CLIENT>
CLIENT> Click Here: http://www.cheapviagra.com
CLIENT> .
SERVER> 250 2.0.0 <dick> Message accepted for delivery: INNOCENT
SERVER> 250 2.0.0 <jane> Message accepted for delivery: SPAM
 
  Optionally, if you'd like the clients to perform delivery, you can use
  DSPAM's --stdout or --classify functionality to obtain a dump of the message
  or results, respectively. From there, it's up to you and your MTA to
  deliver the message. The DSPAM client will output the results to stdout in
  this case, just as it would in standard operating mode.

  Once the server is running, its configuration can be reloaded with a SIGHUP.
  When the daemon is reloaded, the following occurs:

  - The daemon stops listening for new requests
  - All threads are allowed to finish processing and exit
  - All connections to the database are closed
  - The dspam.conf configuration is reloaded
  - All connections to the database are re-opened
  - The daemon starts listening for new requests

  This allows database and listener configurations to also be reloaded from
  dspam.conf without the need to interrupt the process.

  NOTE: During the period of time the daemon is reloading, client connections
  will fail. Depending on how the MTA reacts, this may cause messages to
  fall back to queue or to bounce.

2.4 LMTP 

  DSPAM supports LMTP both on the front-end and back-end (delivery). This
  section will briefly provide instructions for configuring either or both of
  these advanced options.

  LMTP (AND SMTP) DELIVERY

  DSPAM supports LMTP delivery for admins who would prefer to use this instead
  of local delivery. While LMTP delivery doesn't _require_ operating in
  daemon mode, it is necessary to compile DSPAM with --enable-daemon to take
  advantage of LMTP delivery. To configure LMTP delivery, perform the following
  steps:

  1. Compile DSPAM with --enable-daemon to enable LMTP delivery code

  2. Configure your DeliveryHost and DeliveryIdent in dspam.conf. Set 
     DeliveryProto based on whether you would like to delivery via LMTP or SMTP.
f
     NOTE: If you would like to delivery to different hosts based on domain,
     specify DeliveryHost.domain.com as the configuration directive

  3. Add the --lmtp-recipient flag to the arguments passed into DSPAM. This is
     used to specify the destination address for the message. For example, in
     postfix:

     --lmtp-recipient=${recipient}
 
  DSPAM will then connect to the specified host, and deliver using a standard
  LMTP looking like:

LHLO [ident]
MAIL FROM:<> SIZE=[message_length]
RCPT TO: <recipient>
DATA
[Message]
.

  LMTP SERVER

  DSPAM supports a "daemon" mode where it will sit and listen for inbound
  connections. Depending on how the server is configured, DSPAM can speak
  either standard LMTP (for interaction with a mail server, such as postfix)
  or DLMTP (DSPAM LMTP) which is a proprietary implementation of LMTP between
  the DSPAM client and server. If you plan on calling DSPAM from the commandline
  via dspamc, but wish to have a stateful daemon perform processing, then
  you'll want to use the "dspam" server mode. If you want to call DSPAM by
  having your mail server connect to it via LMTP, then you'll need to specify
  the "standard" server mode.

  The ServerMode can be set in dspam.conf. Each mode has its own custom
  tweaks and configurations that will need to be set in dspam.conf. 

  "dspam" mode settings.
  In "dspam" mode, you'll need to set up authentication for each dspam client
  relay. This involves configuring the relay ident and password. Examples are
  provided.
  
  "dspam" mode notes.
  In dspam mode, only the dspam client will be connecting to your LMTP server.
  This can be dspamc (a thin-client) or the dspam binary. In either case,
  you'll need to specify --client to tell DSPAM to act as a client. DLMTP 
  allows the client to pass in any commandline arguments provided, so it should
  function identical to if you were running it as a dedicated (non-stateful)
  process.

  "standard" mode settings.
  In "standard" mode, you will need to configure the ServerParameters flag to
  reflect the commandline parameters you would normally want to pass to DSPAM. 

  "standard" mode notes.
  One thing to watch out for is that the recipient you're sending via LMTP is
  unique to a specific user. This means that all of your aliases should be
  resolved before the MTA relays to DSPAM. Because DSPAM uses the addresses in
  the RCPT TO as usernames, _not_ resolving any aliases will result in
  multiple databases being created for one user. Since the signature will be
  different for each user, and since the message must be processed 
  differently for each user, DSPAM demultiplexes a multi-recipient email. This
  means that while it can receive an email with multiple RCPT TO's specified, it
  will perform delivery individually.

  "auto" mode setting.
  If you would like to support both connecting MTAs and remote dspam client
  processes (such as for inoculations), you can set the server mode to auto,
  which will base its dialect on the ident supplied in the LHLO. If the LHLO
  ident matches an ident in dspam.conf's ServerPass section, the server will
  default to DLMTP. Otherwise, DSPAM will assume the client is a standard 
  LMTP client and speak standard LMTP.

  LOCAL DELIVERY WITH LMTP FRONT-END

  In some circumstances, you may want to relay to DSPAM via LMTP, but have
  DSPAM deliver via LDA. In these cases, you may use the following
  conventions in your ServerParameters configuration:

  %r - The RCPT TO passed in via LMTP 
  %s - The MAIL FROM passed in via LMTP

  In both cases, the content provided between < > is what is actually used.

2.5 DSPAM USER PREFERENCES

  Preferences are settings that can be configured globally in dspam.conf or
  for individual users via the dspam_admin command.

  trainingMode { TOE | TUM | TEFT | NOTRAIN } 
    How DSPAM should train messages it analyzes. See section 1.5 --mode
    (default:teft, see dspam.conf)

  spamAction { quarantine | tag | deliver } 
    What to do with spam. The tag and deliver options both deliver, but tag
    adds a special prefix to the subject, whereas deliver merely sets
    X-DSPAM-Result. (default:quarantine)

  spamSubject 
    A customized subject to prefix when spamAction=tag. (default:[SPAM])

  statisticalSedation { 0 - 10 }
    The level of dampening during training (0-10, 0 = no dampening, default:0)

  enableBNR { on | off }
    Enables or disables bayesian noise reduction (default:off)
 
  enableWhitelist { on | off }
    Enables or disables automatic whitelisting (default:on)

  signatureLocation { message | headers }
    Where to place the DSPAM signature. Placement affects forwarding approach.
    (default:message)

  tagSpam / tagNonspam { on | off }
    Adds a tagline to the end of a message based on its classification; useful
    for things such as "Scanned by Your ISP.com". If set to on, the file
    msgtag.spam and/or msgtag.nonspam will be looked for in dspam_home/txt/
    and appended to appropriate messages. 

    NOTE: Signed messages will not be tagged in this fashion

  showFactors { on | off }
    Whether to include an X-DSPAM-Factors header including decision-making
    factors (clues). NOTE: This can break RFC in some cases, and should only
    be used for debugging. (default:off)

  optIn / optOut { on | off }
    Depending on whether the system is opt-in or opt-out, sets the user's
    membership. If user is opted out (or not opted in), mail will be delivered
    by DSPAM without being processed.

  whitelistThreshold { Integer }
    Overrides the default number of times a From: header has been seen before
    it is automatically whitelisted. (default:10)

  makeCorpus { on | off }
    When activated, a maildir-style corpus is maintained in the user's data
    directory (DSPAM_HOME/DATA/USERNAME), suitable for future retraining or
    other analysis. (default:off)

  storeFragments { on | off }
    When activated, the first 1k of each message are temporarily stored on 
    the server for reference via the webui's history function. (default:off)

  localStore { on | off }
    Overrides the directory name used for the user's dspam data directory. This
    is useful when using recipient addresses as usernames, as it will allow 
    all addresses belonging to a specific user to be written to a single
    webui directory. (default:username)
    
  processorBias { on | off }
    Overrides the "bias" setting in dspam.conf, which biases mail as 
    innocent. (default:on, see dspam.conf)

  fallbackDomain { on | off }
    Allows a dspam user ("@domain.com") to be marked as a fallback user for
    the entire domain, so if the destination dspam user does not exist in
    the database, the fallback user's database will be used. The
    dspam.conf "FallbackDomains" setting must also be "on". (default:off)
    NOTE: You will need to set "FallbackDomains on" in dspam.conf to use this.

  trainPristine { on | off }
    Override's the default signature mode and treats messages as if they were
    in pristine format when retraining. This requires all retraining to use
    the original message that was processed as no dspam signature is stored
    for pristine training. (default:off)

  optOutClamAV { on | off }
    Opts out of ClamAV virus scanning (if ClamAV is directly integrated with
    dspam via dspam.conf). (default:off)

2.6 FALLBACK DOMAINS

  Fallback domains allow you to default some or all users for a particular
  domain to a single domain user; this allows you to set preferences (including
  opting out of filtering entirely) for users based on domain name. Any user
  who does not exist as a known user to DSPAM will be defaulted to the 
  domain it belongs to if it is designated as a fallback domain. This
  means that you can create bob@domain.com and alice@domain.com with their own
  databases and preferences, but also default all other users to @domain.com.
  Alternatively, you could create just the domain without any other users and
  default all users to @domain.com

  To use fallback domains, you'll first need to activate this feature in 
  dspam.conf:

  FallbackDomains on

  Next, you'll need to create a dspam user for each domain you wish to use
  as a fallback domain. For example, @domain.com. Depending on your
  implementation, this may be a simple insert into dspam_virtual_uids or may
  be created automatically when setting a user's preferences.

  Finally, designate that special user as a fallback domain by setting a
  preference: 

  dspam_admin ch pref @domain.com fallbackDomain on

  Any mail coming in for that domain that does _not_ match a known user in 
  dspam will now fall back to this user; you can then set specific preferences
  or even opt out the entire user. Alternatively, you can create a domain-based
  database for filtering mail specific to that domain, just as you would a 
  normal user.

3.0 BUGS, PORTS, AND THE LIKE

  Please see http://dspam.nuclearelephant.com/bugs.shtml for the current known
  bugs list and proper reporting procedure.

  If you port DSPAM to another platform, or would like to submit changes to
  the distribution, please email a diff along with any other pertinent 
  information to the dspam-dev mailing list. 

  Note:

  In order to keep DSPAM unencumbered by intellectual property abuses, all 
  external contributors to the project are asked to release any rights to the 
  submission. This keeps the DSPAM project a healthy, unencumbered GPL project.
  Please accompany your patch, code, or other submission with the following 
  statement. By submitting a patch to the project, you agree to be bound by 
  the terms of this statement whether it is specifically included in the 
  submission or not, however we still require that it be attached to the 
  submission: 

    The author or authors of this submission hereby release any and all 
    copyright interest in this code, documentation, or other materials 
    included to the DSPAM project and its primary governors. We intend this 
    relinquishment of copyright interest in perpetuity of all present and 
    future rights to said submission under copyright law. 

  If you like DSPAM and want to buy the author pizza (or a Ferrari),
  paypal donations may be sent to jonathan@nuclearelephant.com.

  Thanks =)

3.1 CVS ACCESS

  The DSPAM source tree can be downloaded via read-only cvs access using the
  following commands:

  cvs -z3 -d :pserver:cvs@cvs.nuclearelephant.com:/usr/local/cvsroot login
  cvs -z3 -d :pserver:cvs@cvs.nuclearelephant.com:/usr/local/cvsroot co dspam 

  DSPAM has been version-tagged in cvs so that you can checkout a particular
  version by using this format:

  co -r dspam-3_6_0 dspam

