查看“Postfix 完整虚拟邮件系统指南”的源代码




== Abstract ==

There are many howtos in the Internet about setting up mail servers and various people has various choice of MTAs. Some like, Qmail, while some like Postfix or Exim. I have been using Qmail for a long time and it is an excellent MTA. The way the Qmail is licensed and distributed that there are no binary packages so that users can easily setup with their favorite distribution, and installing basic Qmail setup even is not that difficult but users need applied various patches and tweaks etc to get a complete  setup done. With all these issues Qmail is the preferred choice of many geeks, since it won't give you head ache once up and running. The drawback is that this system is difficult to upgrade since users need to compile the source code and install.

The decision behind this guide is to use Postfix,an equally secure and fast MTA like Qmail, it is easy to configure and setup a [https://wiki.ubuntu.com/PostfixBasicSetupHowto Basic System] in any Linux distribution. Postfix has many add-ons and support Maildir format, PostgreSQL and MySQL backend for  storing and managing virtual domains very  easily. This setup will be a complete virtual mail domain systems , with anti-virus and spam filtering for ISPs , hosting companies, and individual corporations who wish to use Ubuntu Linux as there preferred server platform. 

== System Overview ==

It is important to know how our system works before going to install. A virtual mail system needs to be able to handle email for numerous domains with multiple users over a variety of interfaces. When you handle multiple domains within the same mail system it presents you some management issues. We have to answer these issues using  our technology. Assume ,for example you may have following questions to answer.

* What will you do if you have two users which require same username for different domains?

* If you are providing imap access and smtp-auth, how do combine the various authentication daemons into a single system? 

* How do you provide security for the numerous components that comprise the system? 

* What we can do, if users are asking their own spam filtering policies.

* Individual domain administrators are asking a web-based interface to manage their mail domains

* How do you setup a web-based management system for Postfix?

* Each user needs a web-base interface to change his mail account's password

* How you are going backup user account database and disaster recovery?.

* Utilizing ssl for transport layer security

* Handle mailing lists for any domain 

'''How do you manage all these issues together?'''

Don't be panic, I will answer all these questions one by one. Be happy and continue to read this howto. 

=== What You Get ===

* Web based system administration
* Unlimited number of domains
* Virtual mail users without the need for shell accounts
* Domain specific user names
* Mailbox quotas
* Web access to email accounts
* Web base interface to change user passwords
* IMAP and POP3 support
* Auto responders
* SMTP Authentication for secure relaying
* SSL for transport layer security
* Strong SPAM filtering
* Anti-Virus filtering
* Log Analysis

=== Packages Required ===

The following packages are need to implement our system and most of these packages are in APT repositories. In our installation section you will learn how to install and configure each. 

* [http://www.webmin.com/ Webmin]
* [http://www.postfix.org/ Postfix]
* [http://www.mysql.com/ MySQL]
* [http://www.apache.org/ Apache]
* [http://www.php.net/ PHP]
* [http://high5.net/postfixadmin/ Postfixadmin]
* [http://www.courier-mta.org/imap/ Courier-IMAP]
* [http://www.courier-mta.org/?pop3d.html Courier-POP3]
* [http://www.courier-mta.org/authlib/ Courier-authlib]
* [http://asg.web.cmu.edu/sasl/ Cyrus-SASL]
* [http://www.gnu.org/software/ispell/ispell.html Ispell]
* [http://www.squirrelmail.org/ Squirrelmail]
* [http://awstats.sourceforge.net/ Awstats]
* [http://www.ijs.si/software/amavisd/ Amavisd-new]
* [http://spamassassin.apache.org/ Spamassassin]
* [http://www.mailzu.org/ MailZu]
* [http://razor.sourceforge.net/ Razor]
* [http://www.rhyolite.com/anti-spam/dcc/ DCC]
* [http://pyzor.sourceforge.net/ Pyzor]
* [http://sqlgrey.sourceforge.net/ SQLgrey]
* [http://www.vanheusden.com/sgwi/ Sgwi]
* [http://www.clamav.net/ Clamav]

=== The Big Picture ===

The following figure shows the big picture of our setup. If you look at it carefully the figure itself is self explanatory.

attachment:CompleteSetupOverview.png

In our setup:

* '''Postfix''' Mail Transfer Agent receives emails via the SMTP protocol and delivers them to different places on your hard disk.

* '''MySQL''' database server stores the information to control the behavior of postfix. It knows about users, domains, email forwarding and passwords.

* '''Courier''' is a standalone mail server just like Postfix but we just use its POP3/IMAP server component to let users access the mailboxes.

* '''SASL''', the Cyrus library  is using to authenticate  your users who are dialed in at another ISP while they are on the road they get an IP address outside of your network. Your mail server however only trusts local IP addresses. The SASL  ,'''Simple Authentication and Security Layer''', adds authentication to SMTP and makes your mail server trust them.


== How Postfix Mappings Work? ==

It is very important to how Postfix mapping works. Heart of our system is Postfix mapping. Let's discuss it here. Don't skip this section.

The generic literal meaning of mapping is assign one value to another. What we have to map in Postfix is email user accounts or email address. One example is '''<code><nowiki>/etc/aliases</nowiki></code>''', the  local aliases or local system users mapping file used by Postfix. The syntax of this file is:

<pre><nowiki>
postmaster: root
</nowiki></pre>

This makes all the mails which are coming to '''<code><nowiki>postmaster@yourdomain.tld</nowiki></code>''' are redirected to '''<code><nowiki>root@yourdomain.tld</nowiki></code>'''. We can divide the above syntax to Left Hand Side '''LHS''' and Right Hand Side '''RHS'''. This RHS and LHS are common abbreviations which we usually used in mappings. The following table will make this idea even more clear.

{|border="1" cellspacing="0"
|'''LHS'''||'''RHS'''
|-
|postmaster:||root
|}

{|border="1" cellspacing="0"
| attachment:IconHint.png || Usually we do not use colon(:) in LHS for Postfix and this has been done for backward compatibility with historical reasons. The local alias file is a special file that is compiled with '''newaliases''' command but not with usual Postfix mapping command '''postmap'''
|}

With a basic default Postfix installation we use text file for mappings. We write the mappings into this file and then convert it into a '''hash''' file using '''postmap''' command. For example, assume that we need to map our virtual mailboxes in a file called '''<code><nowiki>/etc/Postfix/virtual_mailboxes</nowiki></code>'''. The syntax of this file look like:

<pre><nowiki>
info@domain1.com sigiri
info@domain2.com kala
</nowiki></pre>

You may have noticed that we don't have colon(:) in the '''LHS''' of the mappings file

Then you need to run:

<pre><nowiki>
postmap /etc/postfix/virtual_mailboxes
</nowiki></pre>

You can access this mappings in the Postfix configuration file using the code:

<pre><nowiki>
virtual_mailbox_maps=hash:/etc/postfix/virtual_mailboxes
</nowiki></pre>

In our setup , we will replace this text mapping files by PostgreSQL tables. Our intention is to make data handling lot more flexible, robust, and scalable. But as database tables usually contain more than just two columns you will need to tell Postfix which column is meant to be the LHS and which is the RHS. For same '''virtual_mailbox''' file can be defined in a text file 'like this: 

<pre><nowiki>
user = postfix
password = YJiNLQtubgnOE
hosts = localhost
dbname = postfix
table = mailbox
select_field = maildir
where_field = username
#additional_conditions == and active == '1'
</nowiki></pre>

Let's assume that we save this data in a file called '''<code><nowiki>/etc/postfix/mysql_virtual_mailbox_maps.cf</nowiki></code>'''.

You can use this mappings in postfix using the following entry in '''<code><nowiki>main.cf</nowiki></code>''' file.

<pre><nowiki>
virtual_mailbox_maps = mysql:/usr/local/etc/postfix/pgsql_virtual_mailbox_maps.cf
</nowiki></pre>

The LHS of the mapping is defined as '''<code><nowiki>where_field</nowiki></code>''' and the RHS is defined as '''<code><nowiki>select_field</nowiki></code>'''. In this example we will map the '''
<pre><nowiki>
maildir</nowiki></pre>''' column to the '''<code><nowiki>username</nowiki></code>''' column. The other fields in this definition file are '''user''' that needs to connect to the PostgresSQL database, '''password''' that MySQL user, '''dbname''', the name of the MySQL database, '''table''' ,the name of the table in PostgreSQL database and '''hosts''', the name of the server that MySQL runs on. The following tables may clear the idea even more  better.

{|border="1" cellspacing="0"
|'''LHS'''||'''RHS'''
|-
|select_filed||where_filed
|-
|maildir||username
|}

Other fields:

{|border="1" cellspacing="0"
|'''Database User'''||'''Database User's Password'''||'''Database Name'''||'''Database Table'''||'''Database Host'''
|-
|postfix||YJiNLQtubgnOE||postfix||mailbox||localhost
|}

== How Postfix Virtual Domains Work? ==

Understanding how virtual domains work is very important to understand how our virtual mail setup works. 

There are two types of domains in Postfix. 

* '''Local domains:''' All domains which are listed as '''mydestination''' are treated as '''local domains''' by Postfix. Emails for local domains are delivered to system users which are listed in '''<code><nowiki>/etc/passwd</nowiki></code>''' file and these mails are spooled in '''<code><nowiki>/var/mail</nowiki></code>''' directory. 

* '''Virtual domains:''' In addition to the local domains Postfix can deliver mails for '''virtual domains'''. Not like local domains, Postfix will let us to handle virtual domains in a very flexible manner. The good thing is with virtual domains is that we do not need system account in '''<code><nowiki>/etc/passwd</nowiki></code>''' for each and every mail account. This provides us a way to handle thousands of mail accounts very easily in our mail server system. The mapping which we discussed above is used to handle mail account information.  You can use MySQL, PostgreSQL , or LDAP for the user account management. In our setup we use PostgreSQL backend to manage user accounts of virtual domains.

Postfix handles virtual domains as two different categories and need to understand how they work.


** '''Virtual alias domains:''' These domains are used to forward or alias mails from one email address to another email address. Such domains can be used receive mailboxes and store on your hard disk. You do not necessarily need to use '''virtual alias domains''' in your setup. Instead we can user '''virtual_alias_maps ''' even if the domains are not listed as '''virtual alias domains'''. The '''virtual_alias_maps''' is a general-purpose redirection mapping that works for everything that passes your system including local domains.

** '''Virtual mailbox domains:''' Postfix uses these domains to receive mails for users under the domains and store them in the mailboxes on the hard disk. This is parameter which will simply tell Postfix to receive the mails on behalf of the domain and store them in each user's mailbox. The '''virtual_mailbox_maps''' mapping is used by Postfix to determine the location of the mailbox on your hard disk. Please remember that you can still use the '''virtual_alias_maps''' mapping to forward email to other mailboxes or external email addresses so not every user on that domain must actually have a mailbox but can also just have the email forwarded somewhere else.

{|border="1" cellspacing="0"
| attachment:IconHint.png || It is important to understand that a domain is either a '''virtual alias domain''' or a '''virtual mailbox domain''' or a '''local domain'''. If you make a domain a '''virtual alias domain''' you will not be able to receive email for that domain on your server. On the contrary you can use the '''virtual_alias_maps''' to forward/alias email for both types of domain. So the virtual mailbox domains are generally the more flexible to use.
|}

{|border="1" cellspacing="0"
| attachment:IconWarning.png || A domain can either be virtual or local and you can not use one domain in the both of these roles. Please never both. So if you decide you want your default domain be a virtual domain then remove it from the '''mydestination''' definition. Just leave it blank or set it to '''mydestination=localhost'''. Email addresses like root@localhost would then be delivered to the local '''root''' user.
|}


== Installing a Ubuntu Server System ==

In this howto I assume that you already know how to setup a Ubuntu server system. I would suggest you to do a Ubuntu server installation without a GUI. If you want to know more about installation look [https://wiki.ubuntu.com/Installation here]

== DNS Setup ==

This how to assumes that you already have at least one valid registered domain with an MX record setup for that domain. Setting up a BIND DNS server can be learned [https://wiki.ubuntu.com/BIND9ServerHowto here]

== Package Installation and Configuration ==

You will to have install and configure all packages which I have mentioned in the '''"Package  Required"''' section. Let's deal with one by one.

== Postfix Base Server Installation ==

Here we install Postfix and other packages which Postfix  requires connect with a MysQL backend. 

=== Installing Postfix ===

When you install Postfix I would suggest to select '''"Internet Site"''' option.

To install Postfix:

<pre><nowiki>
sudo apt-get install postfix
</nowiki></pre>

To install postfix documentations:

<pre><nowiki>
sudo apt-get install postfix-doc
</nowiki></pre>

=== Installing  MySQL map support for Postfix ===

We need to add MySQL mapping support for Postfix. Hope that you have already read '''How Postfix Mappings Work?''' section in this howto.

To install postfix-mysql

<pre><nowiki>
sudo apt-get install postfix-mysql
</nowiki></pre>

To install MySQL client program

<pre><nowiki>
sudo apt-get install mysql-client
</nowiki></pre>

To install MySQL server

<pre><nowiki>
sudo apt-get install mysql-server
</nowiki></pre>

== Installing Packages for Client Access and Authentication ==

We will need to offer our user IMAP/POP3 access. Our setup will offer those using the following packages.

To provide client authentication, install:

<pre><nowiki>
sudo apt-get install  courier-authdaemon
</nowiki></pre>

To add MySQL support for courier-authdaemon, Install:

<pre><nowiki>
sudo apt-get install  courier-authmysql
</nowiki></pre>

To provide unencrypted POP3 access, install:

<pre><nowiki>
sudo apt-get install courier-pop
</nowiki></pre>

To provide SSL-encrypted POP3 access, install:

<pre><nowiki>
sudo apt-get install  courier-pop-ssl
</nowiki></pre>

To provide unencrypted IMAP access, install:

<pre><nowiki>
sudo apt-get install  courier-imap
</nowiki></pre>

To provide SSL-encrypted IMAP access , install:

<pre><nowiki>
sudo apt-get install courier-imap-ssl
</nowiki></pre>

== Installing package for SMTP authentication ==

Our system will allow road-warriors to send email through our server using authenticated SMTP. This will basically stop unauthorized relaying through our mail server. Not only we are authenticating our user's when they are retrieving mails but also we authenticate them when they are sending mails as well.

To provide encrypted authenticated SMTP, install:

<pre><nowiki>
sudo apt-get install postfix-tls
</nowiki></pre>

This may have already installed with postfix. If so,leave it.

To install Cyrus SASL library

<pre><nowiki>
sudo apt-get install libsasl2 
</nowiki></pre>

To add authentication mechanisms for the SASL library, install:

<pre><nowiki>
sudo apt-get install  libsasl2-modules
</nowiki></pre>

To add MySQL support authentication mechanisms with the SASL library, install:

<pre><nowiki>
sudo apt-get install  libsasl2-modules-sql
</nowiki></pre>

To create certificates, install:

<pre><nowiki>
sudo apt-get install openssl
</nowiki></pre>

== Setting MySQL Backend ==

Now that we have installed packages required to prepare a MySQL backend for Postfix.   In this section we will configure MySQL database for Postfix.

=== Setting MySQL root Password ===

Please note that MySQL root is different from Linux root account. It is the account   which which users can use to get administrative previlege with MySQL database sever. Initiall installation of MySQL has no password fro root account. If you have not setup a password for MySQL root yet, this is the time for you to do so. There are few ways to do the same and I will present two of them here. Please user either one of them.

To set MySQL root in the comand prompt:

<pre><nowiki>
sudo mysqladmin -u root password rootpassword
</nowiki></pre>

or you can use the following steps to do the same

Type in a terminal

<pre><nowiki>
mysql -u root
</nowiki></pre>

Then in the mysql prompt type:


<pre><nowiki>
mysql>SET PASSWORD FOR 'root'@'localhost' = PASSWORD('rootpasswotd');
mysql>\q
</nowiki></pre>

Don't forget set a good password '''rootpassword'''

=== Setting MySQL Database for Impatient Users ===

The schema is based on the postfixadmin MySQL schema. If you are impatient you can driectly create the tables using following steps. 

<pre><nowiki>
vi postfixadmin-mysql.sql
</nowiki></pre>

Then copy and paste the following script to the above file and save it.

To create the database, type in a terminal.

<pre><nowiki>
mysql -u root -p < postfixadmin-mysql.sql
</nowiki></pre>

<pre><nowiki>
#------------------------------------Start copy-------------------------------------
#
# Postfix Admin
# by Mischa Peters <mischa at high5 dot net>
# Copyright (c) 2002 - 2005 High5!
# License Info: http://www.postfixadmin.com/?file=LICENSE.TXT
#

# This is the complete MySQL database structure for Postfix Admin.
# If you are installing from scratch you can use this file otherwise you
# need to use the TABLE_CHANGES.TXT or TABLE_BACKUP_MX.TXT that comes with Postfix Admin.
#
# There are 2 entries for a database user in the file.
# One you can use for Postfix and one for Postfix Admin.
#
# If you run this file twice (2x) you will get an error on the user creation in MySQL.
# To go around this you can either comment the lines below "USE MySQL" until "USE postfix".
# Or you can remove the users from the database and run it again.
#
# You can create the database from the shell with:
#
# mysql -u root [-p] < DATABASE_MYSQL.TXT

#
# Postfix / MySQL
#
USE mysql;
# Postfix user & password
INSERT INTO user (Host, User, Password) VALUES ('localhost','postfix',password('postfix'));
INSERT INTO db (Host, Db, User, Select_priv) VALUES ('localhost','postfix','postfix','Y');
# Postfix Admin user & password
INSERT INTO user (Host, User, Password) VALUES ('localhost','postfixadmin',password('postfixadmin'));
INSERT INTO db (Host, Db, User, Select_priv, Insert_priv, Update_priv, Delete_priv) VALUES ('localhost', 'postfix', 'postfixadmin', 'Y', 'Y', 'Y', 'Y');
FLUSH PRIVILEGES;
GRANT USAGE ON postfix.* TO postfix@localhost;
GRANT SELECT, INSERT, DELETE, UPDATE ON postfix.* TO postfix@localhost;
GRANT USAGE ON postfix.* TO postfixadmin@localhost;
GRANT SELECT, INSERT, DELETE, UPDATE ON postfix.* TO postfixadmin@localhost;
CREATE DATABASE postfix;
USE postfix;

#
# Table structure for table admin
#
CREATE TABLE admin (
username varchar(255) NOT NULL default '',
password varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
modified datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (username),
KEY username (username)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Admins';

#
# Table structure for table alias
#
CREATE TABLE alias (
address varchar(255) NOT NULL default '',
goto text NOT NULL,
domain varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
modified datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (address),
KEY address (address)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Aliases';

#
# Table structure for table domain
#
CREATE TABLE domain (
domain varchar(255) NOT NULL default '',
description varchar(255) NOT NULL default '',
aliases int(10) NOT NULL default '0',
mailboxes int(10) NOT NULL default '0',
maxquota int(10) NOT NULL default '0',
transport varchar(255) default NULL,
backupmx tinyint(1) NOT NULL default '0',
created datetime NOT NULL default '0000-00-00 00:00:00',
modified datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (domain),
KEY domain (domain)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Domains';

#
# Table structure for table domain_admins
#
CREATE TABLE domain_admins (
username varchar(255) NOT NULL default '',
domain varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
KEY username (username)
) TYPE=MyISAM COMMENT='Postfix Admin - Domain Admins';

#
# Table structure for table log
#
CREATE TABLE log (
timestamp datetime NOT NULL default '0000-00-00 00:00:00',
username varchar(255) NOT NULL default '',
domain varchar(255) NOT NULL default '',
action varchar(255) NOT NULL default '',
data varchar(255) NOT NULL default '',
KEY timestamp (timestamp)
) TYPE=MyISAM COMMENT='Postfix Admin - Log';

#
# Table structure for table mailbox
#
CREATE TABLE mailbox (
username varchar(255) NOT NULL default '',
password varchar(255) NOT NULL default '',
name varchar(255) NOT NULL default '',
maildir varchar(255) NOT NULL default '',
quota int(10) NOT NULL default '0',
domain varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
modified datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (username),
KEY username (username)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Mailboxes';

#
# Table structure for table vacation
#
CREATE TABLE vacation (
email varchar(255) NOT NULL default '',
subject varchar(255) NOT NULL default '',
body text NOT NULL,
cache text NOT NULL,
domain varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (email),
KEY email (email)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Vacation';
#------------------------------------End copy-------------------------------------
</nowiki></pre>

=== Step by Step Database Setup ===

The users who are wish to setup database step by step can use the following steps and understand what table is using what purpose.

==== Setting up Database, Users, and Privileges ====
Connect to MySQL database as root

<pre><nowiki>
mysql -u root -p
</nowiki></pre>

Then type the following sql commands.

To use MySQL user database:

<pre><nowiki>
USE mysql;
</nowiki></pre>

To create Postfix user & set password

<pre><nowiki>
mysql>INSERT INTO user (Host, User, Password) VALUES ('localhost','postfix',password('postfix'));
mysql>INSERT INTO db (Host, Db, User, Select_priv) VALUES ('localhost','postfix','postfix','Y');
</nowiki></pre>

To create Postfix Admin user & set password:

<pre><nowiki>
mysql>INSERT INTO user (Host, User, Password) VALUES ('localhost','postfixadmin',password('postfixadmin'));
mysql>INSERT INTO db (Host, Db, User, Select_priv, Insert_priv, Update_priv, Delete_priv) VALUES ('localhost', 'postfix', 'postfixadmin', 'Y', 'Y', 'Y', 'Y');
mysql>FLUSH PRIVILEGES;
</nowiki></pre>

To Add Privileges for users:

<pre><nowiki>
mysql>GRANT USAGE ON postfix.* TO postfix@localhost;
mysql>GRANT SELECT, INSERT, DELETE, UPDATE ON postfix.* TO postfix@localhost;
mysql>GRANT USAGE ON postfix.* TO postfixadmin@localhost;
mysql>GRANT SELECT, INSERT, DELETE, UPDATE ON postfix.* TO postfixadmin@localhost;
</nowiki></pre>

To create and use the database:

<pre><nowiki>
mysql>CREATE DATABASE postfix;
mysql>USE postfix;
</nowiki></pre>

==== Create the Table Admin ====

This table is used create the administrators for our virtual mail system. The admin user will be able create, modify, and delete virtadomain administrators, mailboxes and other administrative tasks in the mail system. Postfix is not using this table.

Copy and paste the sql statement to your '''mysql>''' prompt.

<pre><nowiki>
CREATE TABLE admin (
username varchar(255) NOT NULL default '',
password varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
modified datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (username),
KEY username (username)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Admins';
</nowiki></pre>

==== Create the Alias table ====

Postfix is using the '''"address"''' and '''"goto"''' column. Courier is not using this table.

{|border="1" cellspacing="0"
| attachment:IconHint.png || This table can be used for virtual .forward files. This table is nothing more than '''<code><nowiki>/etc/aliases</nowiki></code>''' that you will find on any *nix OS. Multiple destination email addresses need to be separated by a "," (comma).
|}

Following is the table structure for table alias. Copy and paste the sql statement to your '''mysql>''' prompt

<pre><nowiki>
CREATE TABLE alias (
address varchar(255) NOT NULL default '',
goto text NOT NULL,
domain varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
modified datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (address),
KEY address (address)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Aliases';
</nowiki></pre>

==== Create the Domain table ====

Postfix is using the '''"domain"''' and '''"description"''' column. Courier is not using this table.

Copy and paste the sql statement to your '''mysql>''' prompt

<pre><nowiki>
CREATE TABLE domain (
domain varchar(255) NOT NULL default '',
description varchar(255) NOT NULL default '',
aliases int(10) NOT NULL default '0',
mailboxes int(10) NOT NULL default '0',
maxquota int(10) NOT NULL default '0',
transport varchar(255) default NULL,
backupmx tinyint(1) NOT NULL default '0',
created datetime NOT NULL default '0000-00-00 00:00:00',
modified datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (domain),
KEY domain (domain)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Domains';

</nowiki></pre>

====  Create the Domain Admin Table ====

Table structure for table domain_admins. This table is used to create individual administrators for each virtual domain. Postfix or Courier is not using this table.

Copy and paste the sql statement to your '''mysql>''' prompt.

<pre><nowiki>
CREATE TABLE domain_admins (
username varchar(255) NOT NULL default '',
domain varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
KEY username (username)
) TYPE=MyISAM COMMENT='Postfix Admin - Domain Admins';
</nowiki></pre>

==== Create the Mailbox Table ====

Postfix is using the '''"username"''' and '''"maildir"''' column while Courier is using the '''"username"''', '''"password"''', '''"name"''' and '''"maildir"''' column.

Copy and paste the sql statement to your '''mysql>''' prompt.

<pre><nowiki>
CREATE TABLE mailbox (
username varchar(255) NOT NULL default '',
password varchar(255) NOT NULL default '',
name varchar(255) NOT NULL default '',
maildir varchar(255) NOT NULL default '',
quota int(10) NOT NULL default '0',
domain varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
modified datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (username),
KEY username (username)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Mailboxes';
</nowiki></pre>

==== Create the Log Table ====

Postfix or Courier is not using this table. Instead this table is used to log the activities of domain administrators and mailbox users.

Copy and paste the sql statement to your '''mysql>''' prompt.

<pre><nowiki>
CREATE TABLE log (
timestamp datetime NOT NULL default '0000-00-00 00:00:00',
username varchar(255) NOT NULL default '',
domain varchar(255) NOT NULL default '',
action varchar(255) NOT NULL default '',
data varchar(255) NOT NULL default '',
KEY timestamp (timestamp)
) TYPE=MyISAM COMMENT='Postfix Admin - Log';
</nowiki></pre>

==== Create the Vacation Table ====

Virual Vacation is  done with a local shell account that can receive
email. The email is then handled by a Perl script which sends the Vacation
message back to the sender. 

Copy and paste the sql statement to your '''mysql>''' prompt.

<pre><nowiki>
CREATE TABLE vacation (
email varchar(255) NOT NULL default '',
subject varchar(255) NOT NULL default '',
body text NOT NULL,
cache text NOT NULL,
domain varchar(255) NOT NULL default '',
created datetime NOT NULL default '0000-00-00 00:00:00',
active tinyint(1) NOT NULL default '1',
PRIMARY KEY  (email),
KEY email (email)
) TYPE=MyISAM COMMENT='Postfix Admin - Virtual Vacation';
</nowiki></pre>

== Setting Postfix MySQL Maps ==

As specified earlier in this document you need to tell Postfix where the control information is stored in the database. You need to create the following four text files in /etc/postfix for that reason.

=== Creating Virtual Alias Maps ===

Postfix will use this file for Virtual Alias Maps and it will use The LHS of the mapping is defined as '''where_field''' and the RHS is defined as '''select_field'''. In this file it would be a mapping of the '''address''' column to the '''goto''' column. 

<pre><nowiki>
sudo vi /etc/postfix/mysql_virtual_alias_maps.cf
</nowiki></pre>

Then add the following code segment to the above file.

<pre><nowiki>
user = postfix
password = postfix
hosts = localhost
dbname = postfix
table = alias
select_field = goto
where_field = address
</nowiki></pre>

=== Virtual Domain Maps ===

Posfix is only using domain filed from this table. For domains we do not need to map LHS and RHS.

<pre><nowiki>
sudo vi /etc/postfix/mysql_virtual_domains_maps.cf
</nowiki></pre>

Then add the following code segment to the above file.

<pre><nowiki>
user = postfix
password = postfix
hosts = localhost
dbname = postfix
table = domain
select_field = domain
where_field = domain
#additional_conditions == and backupmx == '0' and active = '1'
</nowiki></pre>

=== Virtual Mailbox Maps ===

Postfix will map '''username''' column with '''maildir''' querying mailbox table.

<pre><nowiki>
sudo vi mysql_virtual_mailbox_maps.cf
</nowiki></pre>

Then add the following code segment to the above file.

<pre><nowiki>
user = postfix
password = postfix
hosts = localhost
dbname = postfix
table = mailbox
select_field = maildir
where_field = username
#additional_conditions == and active == '1'
</nowiki></pre>

=== Virtual Mailbox Quota Maps ===

Postfix will this maps to handle the quota for virtual mailboxes. '''Username''' column will be mapped with the '''quota''' column in the '''mailbox''' table.

<pre><nowiki>
sudo vi mysql_virtual_mailbox_limit_maps.cf
</nowiki></pre>

Then add the following code segment to the above file.

<pre><nowiki>
user = postfix
password = postfix
hosts = localhost
dbname = postfix
table = mailbox
select_field = quota
where_field = username
#additional_conditions == and active == '1'
</nowiki></pre>

=== Relay Domain Maps ===

If you are going to use your mail system only for hosting backup MX for some virtual  domains then you need this mapping to tell the Postfix to enable the relaying for these domains.

<pre><nowiki>
sudo vi mysql_relay_domains_maps.cf
</nowiki></pre>

Then add the following code segment to the above file.

<pre><nowiki>
user = postfix
password = postfix
hosts = localhost
dbname = postfix
table = domain
select_field = domain
where_field = domain
additional_conditions == and backupmx == '1'
</nowiki></pre>


{|border="1" cellspacing="0"
|attachment:IconWarning.png||For security concerns you should let all these to be read by '''root''' only. If you let other users in the system to read these files, very body on your system can read the '''postfix''' database access password which is written in plain text and find out information about user accounts and alter them in the database. '''Dangerous!!!'''.
|}

Execute the follwing commands to make these file secure from others.

To set the group of these files to postfix:

<pre><nowiki>
sudo chgrp postfix /etc/postfix/mysql_*.cf
</nowiki></pre>

To make the file readable by the group:

<pre><nowiki>
sudo chmod 640 /etc/postfix/mysql_*.cf
</nowiki></pre> 

=== Create a vmail user ===

Our system can hold mailboxes for thousands of users and all these users are virtual  users and non of them is not a Linux system user. Hence these users can not store their mail in our systems hard disk. You probably do not want to assign a unique UID (user ID) to every user. So let's create a Linux user who will become the owner of all mailboxes.

<pre><nowiki>
sudo groupadd -g 5000 vmail
sudo useradd -m -g vmail -u 5000 -d /home/vmail -s /bin/bash vmail
</nowiki></pre>

== Configuring Postfix with MySQL maps ==

We have already created our MySQL maps config files and now the time is to setup Postfix '''main.cf''' file so that Postfix can query MySQL database for virtual mailboxes and domains. 

Open the main.cf file.

<pre><nowiki>
sudo vi /etc/postfix/main.cf
</nowiki></pre>

Then add the following code segment to main.cf

<pre><nowiki>
# Virtual Mailbox Domain Settings

virtual_alias_maps = mysql:/etc/postfix/mysql_virtual_alias_maps.cf
virtual_mailbox_domains = mysql:/etc/postfix/mysql_virtual_domains_maps.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql_virtual_mailbox_maps.cf
virtual_mailbox_limit = 51200000
virtual_minimum_uid = 5000
virtual_uid_maps = static:5000
virtual_gid_maps = static:5000
virtual_mailbox_base = /home/vmail
virtual_transport = virtual

# Additional for quota support

virtual_create_maildirsize = yes
virtual_mailbox_extended = yes
virtual_mailbox_limit_maps = mysql:/etc/postfix/mysql_virtual_mailbox_limit_maps.cf
virtual_mailbox_limit_override = yes
virtual_maildir_limit_message = Sorry, the your maildir has overdrawn your diskspace quota, please free up some of spaces of your mailbox try again.
virtual_overquota_bounce = yes

</nowiki></pre>

== Enhanced Mail Services ==

=== Postfixadmin ===
=== Courier-IMAP and Authentication Services ===
=== SMTP Authentication ===
=== Web Access ===
=== Refining the Setup ===

== Anti-Spam Configuration ==

=== Installing Amavisd and Spamassassin ===
=== Quarantine and Spam Management ===
=== Auto and Per-Recipient White/Black Lists ===
=== Amavis/Spamassassin UI ===
=== GreyListing ===
=== Distributed and Collaborative Networks ===

== Anti-Virus Configuration ==

=== Configuring for ClamAV ===

== Log Analyzer ==

=== Install and Configure AWStats ===

== Wrapping it Up ==

== Final Changes and Troubleshooting ==


Howto created by: ChinthakaDeshapriya.
----
[[category:CategoryDocumentation]] 
[[category:CategoryNeedsExpansion]]