Installing and configuring Spamassassin

May 26, 2024 by Roberto Puzzanghera 49 comments

Info: http://spamassassin.apache.org/
Docs: http://spamassassin.apache.org/full/4.0.x/doc/
Latest version: 4.0.1
Download: http://spamassassin.apache.org/downloads.cgi

SpamAssassin is a mature, widely-deployed open source project that serves as a mail filter to identify Spam. SpamAssassin uses a variety of mechanisms including header and text analysis, Bayesian filtering, DNS blocklists, and collaborative filtering databases. SpamAssassin runs on a server, and filters spam before it reaches your mailbox.

Changelog

May 26, 2024
- SA upgraded to v. 4.0.1
Jun 25, 2023
- The ExtractText notes have been revised and corrected by Gabriel Torres
Jul 14, 2021
- added DCC setup (next page)
- moved the configuration of Razor, Pyzor and Spamcop to a separate page

Upgrading `spamassassin` to version 4.0.x

You have detailed info in a separated page here.

Install

Create the spamd user and group, prepare config and log dirs:

mkdir -p /etc/mail/spamassassin /home/spamd /var/log/spamassassin

groupadd spamd
useradd -g spamd -d /home/spamd spamd
chown -R spamd:spamd /home/spamd

Finally install spamassassin via cpan

perl -MCPAN -e shell
o conf commit prerequisites_policy ask
install Mail::SpamAssassin
quit

Installation notes for Slackware users

REQUIRED module missing: HTML::Parser
REQUIRED module missing: Net::DNS
REQUIRED module missing: NetAddr::IP
REQUIRED module missing: BSD::Resource
optional module missing: Digest::SHA1
optional module missing: Mail::SPF
optional module missing: Razor2
optional module missing: IO::Socket::INET6
optional module missing: IO::Socket::SSL
optional module missing: Mail::DKIM
optional module missing: LWP::UserAgent
optional module missing: HTTP::Date
optional module missing: Encode::Detect
optional module missing: Geo::IP
optional module missing: IO::Socket::IP
optional module missing: Net::Patricia

These modules are missing and must be installed from CPAN. Some of them have dependencies as well...

At the end this is how I have installed everything. Reply yes if dependencies are found, install in this order and force install when needed.

perl -MCPAN -e shell
o conf prerequisites_policy ask

force notest install Socket6 IO::Socket IO::Socket::INET6 LWP MD5 CPAN::DistnameInfo Mail::DKIM

Installed prerequisites of Net::DNS:

force notest install Test::More MIME::Base64 Digest::MD5 Digest::HMAC_MD5 Net::IP

Continue installing these modules (always from CPAN):

force notest install Net::Ping Net::DNS Time::HiRes Digest::SHA1 Getopt::Long Digest::Nilsimsa URI::Escape HTML::Parser HTTP::Date IO::Zlib Archive::Tar  Mail::SPF
force notest install Mail::SPF::Query Net::Ident IO::Socket::SSL Mail::DomainKeys Mail::DKIM LWP::UserAgent HTTP::Date Encode::Detect BSD::Resource
force notest install Storable DB_File Net::SMTP BerkeleyDB
force notest install Geo::IP IO::Socket::IP Net::Patricia
force notest install Mail::DMARC::PurePerl DBD::SQLite

Finally, if everything is ok install spamassassin and Razor via CPAN

force notest install  Mail::SpamAssassin Mail::SpamAssassin::Plugin::Razor2

I had to skip the tests because of many errors... anyway it works.

We have installed the Razor2 perl package that we will see in the next page.

Configuring

You can find the config files into /etc/mail/spamassassin

> cd /etc/mail/spamassassin
> ls
init.pre  local.cf  v310.pre  v312.pre  v320.pre  v330.pre v340.pre  v341.pre  v342.pre  v343.pre  v400.pre

local.cf

# Add *****SPAM***** to the Subject header of spam e-mails
# rewrite_header Subject *****SPAM*****
# put here your subnet
trusted_networks 10.0.0.
# Set the threshold at which a message is considered spam (default: 5.0)
required_score 5.0

`ExtractText`

Thanks to Gabriel Torres for reviewing and correcting this section

The purpose of the ExtractText plugin is to, when enabled, convert attachments (including images, byt the use of an OCR) into plain text in order to SpamAssassin to apply its rules to this text. So if we receive doc/pdf/images with spammy text in them, SpamAssassin will now be able to safely mark the email as spam.

In order to do that, we need to have installed some external programs in our server. The configuration lines added to local.cf have to load these programs to scan each message attachment.

Install the required external programs. Debian users will do;

apt-get install antiword
apt-get install docx2txt
apt-get install unrtf
apt-get install odt2txt
apt-get install tesseract-ocr
apt-get install poppler-utils

Slackware users will find all these programs on SlackBuild, while poppler is already availble in the distro.

Add the following lines to the local.cf file:

ifplugin Mail::SpamAssassin::Plugin::ExtractText

extracttext_external pdftotext /usr/bin/pdftotext -nopgbrk -layout -enc UTF-8 {} -
extracttext_use pdftotext .pdf application/pdf

# http://docx2txt.sourceforge.net
extracttext_external docx2txt /usr/bin/docx2txt {} -
extracttext_use docx2txt .docx application/docx

extracttext_external antiword /usr/bin/antiword -t -w 0 -m UTF-8.txt {}
extracttext_use antiword .doc application/(?:vnd\.?)?ms-?word.*

extracttext_external unrtf /usr/bin/unrtf --nopict {}
extracttext_use unrtf .doc .rtf application/rtf text/rtf

extracttext_external odt2txt /usr/bin/odt2txt --encoding=UTF-8 {}
extracttext_use odt2txt .odt .ott application/.*?opendocument.*text
extracttext_use odt2txt .sdw .stw application/(?:x-)?soffice application/(?:x-)?starwriter

extracttext_external tesseract {OMP_THREAD_LIMIT=1} /usr/bin/tesseract -c page_separator= {} -
extracttext_use tesseract .jpg .png .bmp .tif .tiff image/(?:jpeg|png|x-ms-bmp|tiff)

add_header all ExtractText-Flags _EXTRACTTEXTFLAGS_

#header PDF_NO_TEXT X-ExtractText-Flags =~ /\bNoText\b/
#describe PDF_NO_TEXT PDF without text
#score PDF_NO_TEXT 0.2

#header DOC_NO_TEXT X-ExtractText-Flags =~ /\bNoText\b/
#describe DOC_NO_TEXT Document without text
#score DOC_NO_TEXT 0.2

#header EXTRACTTEXT exists:X-ExtractText-Flags
#describe EXTRACTTEXT Email processed by extracttext plugin
#score EXTRACTTEXT 0.001

endif

You can see three rules commented out. You can safely leave them commented out or enable them for debug purposes. The EXTRACTTEXT rule is just to have proof that the plugin is active. PDF_NO_TEXT and DOC_NO_TEXT will be hit in case of an empty document in attach. You will have an header like this when these two rules have been hit:

X-Spam-ExtractText-Flags: NoText

init.pre

# RelayCountry - add metadata for Bayes learning, marking the countries
# a message was relayed through
#
# Note: This requires the IP::Country::Fast Perl module
#
loadplugin Mail::SpamAssassin::Plugin::RelayCountry

# URIDNSBL - look up URLs found in the message against several DNS
# blocklists.
#
loadplugin Mail::SpamAssassin::Plugin::URIDNSBL

# SPF - perform SPF verification.
#
loadplugin Mail::SpamAssassin::Plugin::SPF

v400.pre

Load all new plugin which come with SA v.4

loadplugin Mail::SpamAssassin::Plugin::ExtractText 
loadplugin Mail::SpamAssassin::Plugin::DecodeShortURLs 
loadplugin Mail::SpamAssassin::Plugin::DMARC

`sa-update`

sa-update updates the rules (it requires gpg 1.4). Before running spamassassin for the first time download the rules:

sa-update

Add to your crontab this line to update the rules once a day

# spamassassin update
30 3 * * * /usr/local/bin/sa-update --nogpg -v &

The -v option will produce an email notification to postmaster.

Testing

Run this debug command. If you get no error you are ready to run the daemon.

sudo -u spamd -H spamassassin -D --lint

Do not quit spamd with ctrl+C, because the next test with spamc will have to connect to it.

Open another terminal and check if the headers are inserted:

echo -e "From: myself@mymailserver.net\nTo:myfriend@domain.net\nSubject: test\n\n" | spamc

Received: from localhost by qmail.mymailserver.net
 with SpamAssassin (version 3.3.1);
 Tue, 30 Nov 2010 23:18:37 +0100
From: myself@mymailserver.net
To: myfriend@domain.net
Subject: test
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-04-18) on qmail.mymailserver.net
X-Spam-Flag: YES
X-Spam-Level: *****
X-Spam-Status: Yes, score=5.4 required=5.0 tests=BAYES_99,FREEMAIL_FROM,
 MISSING_DATE,MISSING_MID,NO_RECEIVED,NO_RELAYS,TVD_SPACE_RATIO,
 T_TO_NO_BRKTS_FREEMAIL autolearn=no version=3.3.1

Running spamassassin

Download the startup script

cd /usr/local/bin
wget https://notes.sagredo.eu/files/qmail/spamdctl
chmod +x spamdctl

You have to replace the IP of your firewall and check that the path where you daemon has been installed (/usr/local/bin/spamd or /usr/local/bin/spamd) matches the one in the run script.

NB: in what follows <external-IP/firewall-IP> is the IP address of your mail server, as seen from the internet.

#!/bin/bash
#
# Spamd init script
#
# August, 2th 2003
# Martin Ostlund, nomicon
# Modified slightly by Troy Belding for Qmailrocks - February 23, 2004
#
# Modified by Roberto Puzzanghera - September 02, 2014
# November 17, 2020: moved log file to /var/log/spamassassin/spamd.log

IP=<external-IP/firewall-IP>
DAEMON=/usr/local/bin/spamd
NAME=spamd
SNAME=spamdctl
DESC="SpamAssassin Mail Filter Daemon"
LOGFILE=/var/log/spamassassin/spamd.log
PIDFILE="/var/run/$NAME.pid"
PNAME="spamd"

DOPTIONS="-x -u spamd -A 127.0.0.1,::1,${IP} -s $LOGFILE -H /home/spamd -d --pidfile=$PIDFILE"

KILL="/bin/kill"
KILLALL="/bin/killall"
# Defaults - don''t touch, edit /etc/mail/spamassassin/local.cf
ENABLED=0
OPTIONS=""

set -e

case "$1" in
start)
echo -n "Starting $DESC: "
$DAEMON $OPTIONS $DOPTIONS

echo "$NAME."
;;
stop)
echo -n "Stopping $DESC: "
$KILL -9 `cat $PIDFILE`
/bin/rm $PIDFILE
echo "$NAME."
;;
restart|force-reload)
echo -n "Restarting $DESC: "
$0 stop
$0 start

echo "$NAME."
;;
*)
ME=/usr/local/bin/$SNAME
echo "Usage: $ME {start|stop|restart|force-reload}" >&2
exit 1
;;
esac

exit 0

Now check that spamd is running:

> spamdctl start
> ps axfu
root      1859  0.1  3.4 139360 61044 ?        Ss   19:00   0:01 /usr/bin/spamd -x -u spamd -A 127.0.0.1,<external-IP> -H /home/spamd -d --pidfile=/var/run/spamd.pid
spamd     1860  0.0  3.2 139360 58984 ?        S    19:00   0:00  \_ spamd child
spamd     1861  0.0  3.2 139360 58984 ?        S    19:00   0:00  \_ spamd child

Type spamd -c to learn how to use spamd. See also http://spamassassin.apache.org/full/3.4.x/doc/spamd.html

Starting spamassassin at boot time

To start spamassassin at boot time put your startup script in your rc.local:

/usr/local/bin/spamdctl start &

logrotate

Create a file /etc/logrotate.d/spamd like this (slackware) to rotate daily your spamd logs:

cat > /etc/logrotate.d/spamd << __EOF__
/var/log/spamassassin/spamd.log /var/log/spamassassin/razor-agent.log {
su root apache
rotate 5
daily
missingok
notifempty
delaycompress
postrotate
   [ -f '/var/run/spamd.pid' ] && (kill -HUP `cat /var/run/spamd.pid`) || exit 0
endscript
}
__EOF__

Be aware that we have already setup the logrotate for the log file or Razor, which we'll see in the next page.

vpopmail-auth driver patch

Filtering networks

spamassassin

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Comments

Installing spamassassin

Arkadiusz Bronowicki November 30, 2024 10:29 CET

I'm assuming it's me doing something wrong and not knowing how to do something, but I follow the command by command, step by step and I'm not able to install spamassassin.

I have this message :(

t/sa_check_spamd.t ................ spam_pid not found:

Sleeping 5 - Retry # 19
Sleeping 5 - Retry # 18
Sleeping 6 - Retry # 17
spam_pid not found:

Sleeping 6 - Retry # 16

What now?

My system is Debian 12.

all the best

Arek

Installing and configuring Spamassassin

Changelog

Upgrading spamassassin to version 4.0.x

Install

Installation notes for Slackware users

Configuring

local.cf

ExtractText

init.pre

v400.pre

sa-update

Testing

Running spamassassin

Starting spamassassin at boot time

logrotate

Comments

qmail notes

LXC scripts

Other contents

Recent comments

See also...

Recent posts

Upgrading `spamassassin` to version 4.0.x

`ExtractText`

`sa-update`