Virtual Users And Domains With Postfix, Courier And MySQL (Ubuntu 7.10) - Page 2

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Submitted by falko (Contact Author) (Forums) on Thu, 2007-11-22 17:38. ::

4 Create The MySQL Database For Postfix/Courier

Now we create a database called mail:

mysqladmin -u root -p create mail

Next, we go to the MySQL shell:

mysql -u root -p

On the MySQL shell, we create the user mail_admin with the passwort mail_admin_password (replace it with your own password) who has SELECT,INSERT,UPDATE,DELETE privileges on the mail database. This user will be used by Postfix and Courier to connect to the mail database:

GRANT SELECT, INSERT, UPDATE, DELETE ON mail.* TO 'mail_admin'@'localhost' IDENTIFIED BY 'mail_admin_password';
GRANT SELECT, INSERT, UPDATE, DELETE ON mail.* TO 'mail_admin'@'localhost.localdomain' IDENTIFIED BY 'mail_admin_password';
FLUSH PRIVILEGES;

Still on the MySQL shell, we create the tables Postfix and Courier need:

USE mail;

CREATE TABLE domains (
domain varchar(50) NOT NULL,
PRIMARY KEY (domain) )
TYPE=MyISAM;

CREATE TABLE forwardings (
source varchar(80) NOT NULL,
destination TEXT NOT NULL,
PRIMARY KEY (source) )
TYPE=MyISAM;

CREATE TABLE users (
email varchar(80) NOT NULL,
password varchar(20) NOT NULL,
quota INT(10) DEFAULT '10485760',
PRIMARY KEY (email)
) TYPE=MyISAM;

CREATE TABLE transport (
domain varchar(128) NOT NULL default '',
transport varchar(128) NOT NULL default '',
UNIQUE KEY domain (domain)
) TYPE=MyISAM;

quit;

As you may have noticed, with the quit; command we have left the MySQL shell and are back on the Linux shell.

The domains table will store each virtual domain that Postfix should receive emails for (e.g. example.com).

domain
example.com

The forwardings table is for aliasing one email address to another, e.g. forward emails for info@example.com to sales@example.com.

source destination
info@example.com sales@example.com

The users table stores all virtual users (i.e. email addresses, because the email address and user name is the same) and passwords (in encrypted form!) and a quota value for each mail box (in this example the default value is 10485760 bytes which means 10MB).

email password quota
sales@example.com No9.E4skNvGa. ("secret" in encrypted form) 10485760

The transport table is optional, it is for advanced users. It allows to forward mails for single users, whole domains or all mails to another server. For example,

domain transport
example.com smtp:[1.2.3.4]

would forward all emails for example.com via the smtp protocol to the server with the IP address 1.2.3.4 (the square brackets [] mean "do not make a lookup of the MX DNS record" (which makes sense for IP addresses...). If you use a fully qualified domain name (FQDN) instead you would not use the square brackets.).

BTW, (I'm assuming that the IP address of your mail server system is 192.168.0.100) you can access phpMyAdmin over http://192.168.0.100/phpmyadmin/ in a browser and log in as mail_admin. Then you can have a look at the database. Later on you can use phpMyAdmin to administrate your mail server.

 

5 Configure Postfix

Now we have to tell Postfix where it can find all the information in the database. Therefore we have to create six text files. You will notice that I tell Postfix to connect to MySQL on the IP address 127.0.0.1 instead of localhost. This is because Postfix is running in a chroot jail and does not have access to the MySQL socket which it would try to connect if I told Postfix to use localhost. If I use 127.0.0.1 Postfix uses TCP networking to connect to MySQL which is no problem even in a chroot jail (the alternative would be to move the MySQL socket into the chroot jail which causes some other problems).

Please make sure that /etc/mysql/my.cnf contains the following line:

vi /etc/mysql/my.cnf

[...]
bind-address            = 127.0.0.1
[...]

If you had to modify /etc/mysql/my.cnf, please restart MySQL now:

/etc/init.d/mysql restart

Run

netstat -tap | grep mysql

to make sure that MySQL is listening on 127.0.0.1 (localhost.localdomain):

root@server1:~# netstat -tap | grep mysql
tcp        0      0 localhost.localdo:mysql *:*                     LISTEN     5742/mysqld
root@server1:~#

Now let's create our six text files.

vi /etc/postfix/mysql-virtual_domains.cf

user = mail_admin
password = mail_admin_password
dbname = mail
query = SELECT domain AS virtual FROM domains WHERE domain='%s'
hosts = 127.0.0.1

vi /etc/postfix/mysql-virtual_forwardings.cf

user = mail_admin
password = mail_admin_password
dbname = mail
query = SELECT destination FROM forwardings WHERE source='%s'
hosts = 127.0.0.1

vi /etc/postfix/mysql-virtual_mailboxes.cf

user = mail_admin
password = mail_admin_password
dbname = mail
query = SELECT CONCAT(SUBSTRING_INDEX(email,'@',-1),'/',SUBSTRING_INDEX(email,'@',1),'/') FROM users WHERE email='%s'
hosts = 127.0.0.1

vi /etc/postfix/mysql-virtual_email2email.cf

user = mail_admin
password = mail_admin_password
dbname = mail
query = SELECT email FROM users WHERE email='%s'
hosts = 127.0.0.1

vi /etc/postfix/mysql-virtual_transports.cf

user = mail_admin
password = mail_admin_password
dbname = mail
query = SELECT transport FROM transport WHERE domain='%s'
hosts = 127.0.0.1

vi /etc/postfix/mysql-virtual_mailbox_limit_maps.cf

user = mail_admin
password = mail_admin_password
dbname = mail
query = SELECT quota FROM users WHERE email='%s'
hosts = 127.0.0.1

Then change the permissions and the group of these files:

chmod o= /etc/postfix/mysql-virtual_*.cf
chgrp postfix /etc/postfix/mysql-virtual_*.cf

Now we create a user and group called vmail with the home directory /home/vmail. This is where all mail boxes will be stored.

groupadd -g 5000 vmail
useradd -g vmail -u 5000 vmail -d /home/vmail -m

Next we do some Postfix configuration. Go sure that you replace server1.example.com with a valid FQDN, otherwise your Postfix might not work properly!

postconf -e 'myhostname = server1.example.com'
postconf -e 'mydestination = server1.example.com, localhost, localhost.localdomain'
postconf -e 'mynetworks = 127.0.0.0/8'
postconf -e 'virtual_alias_domains ='
postconf -e 'virtual_alias_maps = proxy:mysql:/etc/postfix/mysql-virtual_forwardings.cf, mysql:/etc/postfix/mysql-virtual_email2email.cf'
postconf -e 'virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql-virtual_domains.cf'
postconf -e 'virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailboxes.cf'
postconf -e 'virtual_mailbox_base = /home/vmail'
postconf -e 'virtual_uid_maps = static:5000'
postconf -e 'virtual_gid_maps = static:5000'
postconf -e 'smtpd_sasl_auth_enable = yes'
postconf -e 'broken_sasl_auth_clients = yes'
postconf -e 'smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination'
postconf -e 'smtpd_use_tls = yes'
postconf -e 'smtpd_tls_cert_file = /etc/postfix/smtpd.cert'
postconf -e 'smtpd_tls_key_file = /etc/postfix/smtpd.key'
postconf -e 'transport_maps = proxy:mysql:/etc/postfix/mysql-virtual_transports.cf'
postconf -e 'virtual_create_maildirsize = yes'
postconf -e 'virtual_maildir_extended = yes'
postconf -e 'virtual_mailbox_limit_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailbox_limit_maps.cf'
postconf -e 'virtual_mailbox_limit_override = yes'
postconf -e 'virtual_maildir_limit_message = "The user you are trying to reach is over quota."'
postconf -e 'virtual_overquota_bounce = yes'
postconf -e 'proxy_read_maps = $local_recipient_maps $mydestination $virtual_alias_maps $virtual_alias_domains $virtual_mailbox_maps $virtual_mailbox_domains $relay_recipient_maps $relay_domains $canonical_maps $sender_canonical_maps $recipient_canonical_maps $relocated_maps $transport_maps $mynetworks $virtual_mailbox_limit_maps'

Afterwards we create the SSL certificate that is needed for TLS:

cd /etc/postfix
openssl req -new -outform PEM -out smtpd.cert -newkey rsa:2048 -nodes -keyout smtpd.key -keyform PEM -days 365 -x509

Country Name (2 letter code) [AU]: <-- Enter your Country Name (e.g., "DE").
State or Province Name (full name) [Some-State]:
<-- Enter your State or Province Name.
Locality Name (eg, city) []:
<-- Enter your City.
Organization Name (eg, company) [Internet Widgits Pty Ltd]:
<-- Enter your Organization Name (e.g., the name of your company).
Organizational Unit Name (eg, section) []:
<-- Enter your Organizational Unit Name (e.g. "IT Department").
Common Name (eg, YOUR name) []:
<-- Enter the Fully Qualified Domain Name of the system (e.g. "server1.example.com").
Email Address []:
<-- Enter your Email Address.

Then change the permissions of the smtpd.key:

chmod o= /etc/postfix/smtpd.key


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Submitted by zcox123 (registered user) on Tue, 2008-03-18 16:48.

If you include your hostname in the domains table, you should use this as the first postconf setting above for mydestination:

postconf -e 'mydestination = localhost, localhost.localdomain'

In other words, if your server1.example.com is mydomain.com, do not include mydomain.com in that list for mydestination if it is in the domains table, otherwise /var/log/mail.warn will give you lines like this, and email to mydomain.com will get bounced:

warning: do not list domain mydomain.com in BOTH mydestination and virtual_mailbox_domains

Otherwise, I followed this tutorial line-by-line and it works perfectly on Ubuntu 7.10 - nice work!