So I decided to install Spamassassin and Clamav to detect and reject some of this spam.

First of all, we need to install needed packages:

apt-get install spamassassin amavisd-new clamav clamav-daemon

We will begin configuring amavisd-new, the configuration files are at /etc/amavis/conf.

In file 20-debian_defaults I changed the header that will be added to each mail processed:

$X_HEADER_LINE = "AntiSpam/Antivirus Scanner at $mydomain";

We need to activate antispam and antivirus check in amavis, this is found in file 15-content_filter_mode. We need to uncomment @bypass_virus_checks_maps and @bypass_spam_checks_maps. The file will 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
# Please note, that anti-virus checking is DISABLED by
# default.
# If You wish to enable it, please uncomment the following lines:
 
 
@bypass_virus_checks_maps = (
   \%bypass_virus_checks, \@bypass_virus_checks_acl, \$bypass_virus_checks_re);
 
 
#
# Default SPAM checking mode
# Please note, that anti-spam checking is DISABLED by
# default.
# If You wish to enable it, please uncomment the following lines:
 
 
@bypass_spam_checks_maps = (
   \%bypass_spam_checks, \@bypass_spam_checks_acl, \$bypass_spam_checks_re);
 
1;  # ensure a defined return

By default, amavis will use the hostname for $mydomain, but thats not what I want, so I edited file 05-domain_id, setting $mydomain to binware.org

use strict;
 
# $mydomain is used just for convenience in the config files and it is not
# used internally by amavisd-new except in the default X_HEADER_LINE (which
# Debian overrides by default anyway).
 
$mydomain = 'binware.org';
 
# amavisd-new needs to know which email domains are to be considered local
# to the administrative domain.  Only emails to "local" domains are subject
# to certain functionality, such as the addition of spam tags.
#
# Default local domains to $mydomain and all subdomains.  Remember to
# override or redefine this if $mydomain is changed later in the config
# sequence.
 
@local_domains_acl = ( ".$mydomain" );
 
1;  # ensure a defined return

Next step is to add the clamav user to the amavis group, so that amavis can call clamav

adduser clamav amavis

Now it's time to configure postfix. The first file to edit is main.cf:

# Amavisd-new
content_filter = amavis:[127.0.0.1]:10024

And in master.conf add this at the end of file:

amavis unix - - - - 2 smtp
  -o smtp_data_done_timeout=1200
  -o smtp_send_xforward_command=yes
 
127.0.0.1:10025 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=127.0.0.0/8
  -o strict_rfc821_envelopes=yes
  -o smtpd_bind_address=127.0.0.1

That's all! Now restart services:

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

Como tengo ahora mismo todo configurado con los paquetes de debian, he pensado que lo mejor es parchear los propios paquetes de debian, y aqui estan los pasos que he seguido:

1. Instalo todas las utilidades necesarias para poder compilar y crear el paquete de postfix.

   apt-get install build-essential dpkg-dev fakeroot debhelper po-debconf dpatch lsb-release libdb4.3-dev libgdbm-dev libldap2-dev libpcre3-dev libmysqlclient15-dev libsasl2-dev libpq-dev

2. Nos bajamos el codigo fuente del postfix (Conviene hacerlo en /usr/src ya que lo descarga en el directorio actual)

   apt-get source postfix

3. Nos bajamos el ultimo parche disponible para nuestra version de http://web.onda.com.br/nadal/

   wget http://web.onda.com.br/nadal/postfix/VDA/postfix-2.2.8-vda.patch.gz

4. Parcheamos el codigo

   gunzip postfix-2.2.8-vda.patch.gz
   patch -p1

5. Compilamos

   dpkg-buildpackage

6. Instalamos los paquetes generados

   dpkg -i postfix_2.2.8-9_i386.deb
   dpkg -i postfix-mysql_2.2.8-9_i386.deb

7. Configuramos postfix

1. main.cf

   virtual_mailbox_limit_override=yes
   #Use IMAP compatible files
   virtual_maildir_extended=yes
   #Create maildirsize files
   virtual_create_maildirsize=yes
   #Bounce mails overquota
   virtual_overquota_bounce=yes
   #MySQL info to get user quota
   virtual_mailbox_limit_maps=mysql:/etc/postfix/quota.cf
   #Count Trash
   virtual_trash_count=yes
   virtual_trash_name=.Trash

2. quota.cf

   user=mail
   password=mailpassword
   dbname=mail
   table=users
   hosts=localhost
   where_field=address
   select_field=quota

1. authmysqlrc

   MYSQL_QUOTA_FIELD quota

Updated (2007/07/12): La nueva URL del patch VDA es http://vda.sourceforge.net/

Por lo tanto he decido que voy a aprovechar lo que trae el VHCS y cogerlo como base para diseñarme mi propio panel teniendo Bind-Mysql, Postfix/Courier-Mysql y Proftpd-Mysql. Modificar la base de datos es mucho mejor que tener que tocar archivos de sistema y ir dando permisos a programas.