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

CREATE TABLE domains (
DOMAIN VARCHAR(50) NOT NULL,
PRIMARY KEY (DOMAIN) )
ENGINE=MyISAM;
 
CREATE TABLE forwardings (
SOURCE VARCHAR(80) NOT NULL,
destination TEXT NOT NULL,
PRIMARY KEY (SOURCE) )
ENGINE=MyISAM;
 
CREATE TABLE users (
email VARCHAR(80) NOT NULL,
password VARCHAR(20) NOT NULL,
quota INT(10) DEFAULT '10485760',
PRIMARY KEY (email)
) ENGINE=MyISAM;
 
CREATE TABLE transport (
DOMAIN VARCHAR(128) NOT NULL DEFAULT '',
transport VARCHAR(128) NOT NULL DEFAULT '',
UNIQUE KEY DOMAIN (DOMAIN)
) ENGINE=MyISAM;

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

apt-get install postfix postfix-mysql dovecot-core dovecot-imapd dovecot-lmtpd dovecot-mysql