There is a new version of this tutorial available for Ubuntu 13.10 (Saucy Salamander).

Virtual Users And Domains With Postfix, Courier, MySQL And SquirrelMail (Ubuntu 8.04 LTS) - Page 3

9 Install amavisd-new, SpamAssassin, And ClamAV

To install amavisd-new, spamassassin and clamav, run the following command:

apt-get install amavisd-new spamassassin clamav clamav-daemon zoo unzip bzip2 unzoo libnet-ph-perl libnet-snpp-perl libnet-telnet-perl nomarch lzop pax

Afterwards we must configure amavisd-new. The configuration is split up in various files which reside in the /etc/amavis/conf.d directory. Take a look at each of them to become familiar with the configuration. Most settings are fine, however we must modify three files:

First we must enable ClamAV and SpamAssassin in /etc/amavis/conf.d/15-content_filter_mode by uncommenting the @bypass_virus_checks_maps and the @bypass_spam_checks_maps lines:

vi /etc/amavis/conf.d/15-content_filter_mode

The file should look like this:

use strict;

# You can modify this file to re-enable SPAM checking through spamassassin
# and to re-enable antivirus checking.

# Default antivirus checking mode
# Uncomment the two lines below to enable it back

@bypass_virus_checks_maps = (
   \%bypass_virus_checks, \@bypass_virus_checks_acl, \$bypass_virus_checks_re);

# Default SPAM checking mode
# Uncomment the two lines below to enable it back

@bypass_spam_checks_maps = (
   \%bypass_spam_checks, \@bypass_spam_checks_acl, \$bypass_spam_checks_re);

1;  # ensure a defined return

And then you should take a look at the spam settings and the actions for spam-/virus-mails in /etc/amavis/conf.d/20-debian_defaults. There's no need to change anything if the default settings are ok for you. The file contains many explanations so there's no need to explain the settings here:

vi /etc/amavis/conf.d/20-debian_defaults

$QUARANTINEDIR = "$MYHOME/virusmails";
$quarantine_subdir_levels = 1; # enable quarantine dir hashing

$log_recip_templ = undef;    # disable by-recipient level-0 log entries
$DO_SYSLOG = 1;              # log via syslogd (preferred)
$syslog_ident = 'amavis';    # syslog ident tag, prepended to all messages
$syslog_facility = 'mail';
$syslog_priority = 'debug';  # switch to info to drop debug output, etc

$enable_db = 1;              # enable use of BerkeleyDB/libdb (SNMP and nanny)
$enable_global_cache = 1;    # enable use of libdb-based cache if $enable_db=1

$inet_socket_port = 10024;   # default listening socket

$sa_spam_subject_tag = '***SPAM*** ';
$sa_tag_level_deflt  = 2.0;  # add spam info headers if at, or above that level
$sa_tag2_level_deflt = 6.31; # add 'spam detected' headers at that level
$sa_kill_level_deflt = 6.31; # triggers spam evasive actions
$sa_dsn_cutoff_level = 10;   # spam level beyond which a DSN is not sent

$sa_mail_body_size_limit = 200*1024; # don't waste time on SA if mail is larger
$sa_local_tests_only = 0;    # only tests which do not require internet access?

$final_virus_destiny      = D_DISCARD;  # (data not lost, see virus quarantine)
$final_banned_destiny     = D_BOUNCE;   # D_REJECT when front-end MTA
$final_spam_destiny       = D_BOUNCE;
$final_bad_header_destiny = D_PASS;     # False-positive prone (for spam)

Finally, edit /etc/amavis/conf.d/50-user and add the line $pax='pax'; in the middle:

vi /etc/amavis/conf.d/50-user

use strict;

# Place your configuration directives here.  They will override those in
# earlier files.
# See /usr/share/doc/amavisd-new/ for documentation and examples of
# the directives you can use in this file


#------------ Do not modify anything below this line -------------
1;  # ensure a defined return

Afterwards, run these commands to add the clamav user to the amavis group and to restart amavisd-new and ClamAV:

adduser clamav amavis
/etc/init.d/amavis restart
/etc/init.d/clamav-daemon restart
/etc/init.d/clamav-freshclam restart

Now we have to configure Postfix to pipe incoming email through amavisd-new:

postconf -e 'content_filter = amavis:[]:10024'
postconf -e 'receive_override_options = no_address_mappings'

Afterwards append the following lines to /etc/postfix/

vi /etc/postfix/

amavis unix - - - - 2 smtp
        -o smtp_data_done_timeout=1200
        -o smtp_send_xforward_command=yes inet n - - - - smtpd
        -o content_filter=
        -o local_recipient_maps=
        -o relay_recipient_maps=
        -o smtpd_restriction_classes=
        -o smtpd_client_restrictions=
        -o smtpd_helo_restrictions=
        -o smtpd_sender_restrictions=
        -o smtpd_recipient_restrictions=permit_mynetworks,reject
        -o mynetworks=
        -o strict_rfc821_envelopes=yes
        -o receive_override_options=no_unknown_recipient_checks,no_header_body_checks
        -o smtpd_bind_address=

Then restart Postfix:

/etc/init.d/postfix restart

Now run

netstat -tap

and you should see Postfix (master) listening on port 25 (smtp) and 10025, and amavisd-new on port 10024:

[email protected]:/etc/postfix# netstat -tap
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 localhost.localdo:10024 *:*                     LISTEN      15645/amavisd (mast
tcp        0      0 localhost.localdo:10025 *:*                     LISTEN      16677/master
tcp        0      0 localhost.localdo:mysql *:*                     LISTEN      6177/mysqld
tcp        0      0 *:www                   *:*                     LISTEN      5367/apache2
tcp        0      0 *:smtp                  *:*                     LISTEN      16677/master
tcp6       0      0 [::]:imaps              [::]:*                  LISTEN      14020/couriertcpd
tcp6       0      0 [::]:pop3s              [::]:*                  LISTEN      14088/couriertcpd
tcp6       0      0 [::]:pop3               [::]:*                  LISTEN      14051/couriertcpd
tcp6       0      0 [::]:imap2              [::]:*                  LISTEN      13983/couriertcpd
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN      4006/sshd
tcp6       0     52 ESTABLISHED 4059/0
[email protected]:/etc/postfix#


10 Install Razor, Pyzor And DCC And Configure SpamAssassin

Razor, Pyzor and DCC are spamfilters that use a collaborative filtering network. To install Razor and Pyzor, run

apt-get install razor pyzor

DCC isn't available in the Ubuntu 8.04 repositories, so we install it as follows:

cd /tmp
dpkg -i dcc-common_1.3.42-5_i386.deb
dpkg -i dcc-server_1.3.42-5_i386.deb

Now we have to tell SpamAssassin to use these three programs. Edit /etc/spamassassin/ and add the following lines to it:

vi /etc/spamassassin/

use_dcc 1
dcc_path /usr/bin/dccproc

use_pyzor 1
pyzor_path /usr/bin/pyzor

use_razor2 1
razor_config /etc/razor/razor-agent.conf

use_bayes 1
use_bayes_rules 1
bayes_auto_learn 1

Then we must enable the DCC plugin in SpamAssassin. Open /etc/spamassassin/v310.pre and uncomment the loadplugin Mail::SpamAssassin::Plugin::DCC line:

vi /etc/spamassassin/v310.pre

# DCC - perform DCC message checks.
# DCC is disabled here because it is not open source.  See the DCC
# license for more details.
loadplugin Mail::SpamAssassin::Plugin::DCC

You can check your SpamAssassin configuration by executing:

spamassassin --lint

It shouldn't show any errors.

Restart amavisd-new afterwards:

/etc/init.d/amavis restart

Now we update our SpamAssassin rulesets as follows:

sa-update --no-gpg

We create a cron job so that the rulesets will be updated regularly. Run

crontab -e

to open the cron job editor. Create the following cron job:

23 4 */2 * * /usr/bin/sa-update --no-gpg &> /dev/null

This will update the rulesets every second day at 4.23h.


11 Quota Exceedance Notifications

If you want to get notifications about all the email accounts that are over quota, then do this:

cd /usr/local/sbin/
mv quota.txt quota_notify
chmod 755 quota_notify

Open /usr/local/sbin/quota_notify and edit the variables at the top. Further down in the file (towards the end) there are two lines where you should add a % sign:

vi /usr/local/sbin/quota_notify

my $POSTFIX_CF = "/etc/postfix/";
my $MAILPROG = "/usr/sbin/sendmail -t";
my @POSTMASTERS = ('[email protected]');
my $CONAME = 'My Company';
my $COADDR = '[email protected]';
my $SUADDR = '[email protected]';
my $MAIL_REPORT = 1;
           print "Subject: WARNING: Your mailbox is $lusers{$luser}% full.\n";
           print "Your mailbox: $luser is $lusers{$luser}% full.\n\n";


crontab -e

to create a cron job for that script:

0 0 * * * /usr/local/sbin/quota_notify &> /dev/null
Falko Timme

About Falko Timme

Falko Timme is an experienced Linux administrator and founder of Timme Hosting, a leading nginx business hosting company in Germany. He is one of the most active authors on HowtoForge since 2005 and one of the core developers of ISPConfig since 2000. He has also contributed to the O'Reilly book "Linux System Administration".

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3 Comment(s)

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By: Eric Thelin

For a 64bit server use these urls in step 10 to get DCC instead of the ones listed.

By: Fred

I got an error when I wanted to send mail, even to an internal account.

I checked the conf again and again until I discvered that amavis was not activated (with netstat -tap).

When I tried to launch amavis I got the following error : 

Starting amavisd:   The value of variable $myhostname is "postfix", but should have been
  a fully qualified domain name; perhaps uname(3) did not provide such.
  You must explicitly assign a FQDN of this host to variable $myhostname
  in /etc/amavis/conf.d/05-node_id, or fix what uname(3) provides as a host's
  network name!

I checked my hostname and realized it was not correctly configured.
I jut set it to, started Amavis, restarted postfix, and evvery thing is running fine, now.


By: TallPaul

Assuming that you have anacron installed then in 10. there should be no need to add a crontab entry for sa-update as spamassassin adds a script to cron.daily to do this automagically.