Today I will be writing about how to set up your own email server.
You will need the following build for your server
- Linux OS – Ubuntu 14.04
- Apache 2
- MySQL Database
- PHP 5
- Root Access
This guide shows you how to set up a secure mail server with Postfix, Dovecot, and MySQL.
By the end of this tutorial, you’ll know how to create mail box for your users, to send and receive email for your domains.
Mail Components
Postfix for Mail Transfer Agent, its the controller of mail server, that decide if a particular user can send email, and how to relay email.
Dovecot – It handle the protocol of IMAP and POP3, allow users to login and check for their mail. It also help save mail files on your server, and the authorization. It query MYSQL database to check for user email and password before allow a mail to be send or view.
MYSQL – The database server to store mail particulars such as domain, aliases, and user accounts
Step 1 – Connect to your server
After logged in, Log in as the root user by entering the following command:
su
Key in the password for the root user.
Next, you need to install this required library
sudo apt-get install postfix postfix-mysql dovecot-core dovecot-imapd dovecot-pop3d dovecot-lmtpd dovecot-mysql
You’ll be prompted to select a Postfix configuration. Select Internet Site, as shown below.
Selection: Internet Site
You’ll be prompted to enter a System mail name, as shown below. For our example we use mail.example.com, you can use any hostname you want (we will setup this on the next stage, just think of a name you want first)
Setup Host Name
Now type the following code below, for this tutorial I use nano editor, you can use vim if you want to.
nano /etc/hostname
Next we edit the host records using the command below
nano /etc/hosts
MySQL Database Setup
Now we begin create the necessary tables & records for mail server.
First we login to mysql database
mysql -u root -pYOURSQLPASSWORD
Take note that everyone mysql root password is different, you have to change the value of YOURSQLPASSWORD to your mysql password.
You will see the screen above upon mysql login
Next we will create the database, using the command below
create database mailserver
Next we will create a mysql user and grant the permission to access the database
CREATE USER ‘demouser’@’localhost’ IDENTIFIED BY ‘pass.1234′;
GRANT ALL PRIVILEGES ON *.* TO ‘demouser’@’%’ WITH GRANT OPTION; FLUSH PRIVILEGES;
Next we will create the table for domain
CREATE TABLE `virtual_domains` ( `id` int(11) NOT NULL auto_increment, `name` varchar(50) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
We will also create the table for email users
CREATE TABLE `virtual_users` ( `id` int(11) NOT NULL auto_increment, `domain_id` int(11) NOT NULL, `password` varchar(106) NOT NULL, `email` varchar(100) NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY `email` (`email`), FOREIGN KEY (domain_id) REFERENCES virtual_domains(id) ON DELETE CASCADE ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
And also the aliases list – email forwarding
CREATE TABLE `virtual_aliases` ( `id` int(11) NOT NULL auto_increment, `domain_id` int(11) NOT NULL, `source` varchar(100) NOT NULL, `destination` varchar(100) NOT NULL, PRIMARY KEY (`id`), FOREIGN KEY (domain_id) REFERENCES virtual_domains(id) ON DELETE CASCADE ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Next we will begin adding the data, do change the value to suit your domain & user.
INSERT INTO `mailserver`.`virtual_domains` (`id` ,`name`) VALUES (‘1′, ‘example.com’), (‘2′, ‘hostname.example.com’), (‘3′, ‘hostname’), (‘4′, ‘localhost.example.com’);
Next we create the email login details
INSERT INTO `mailserver`.`virtual_users` (`id`, `domain_id`, `password` , `email`) VALUES (‘1′, ‘1’, ENCRYPT(‘firstpassword’, CONCAT(‘$6$’, SUBSTRING(SHA(RAND()), -16))), ‘email1@example.com’), (‘2′, ‘1’, ENCRYPT(‘secondpassword’, CONCAT(‘$6$’, SUBSTRING(SHA(RAND()), -16))), ‘email2@example.com’);
For this example above, we created the email user email1@example.com with the login password “ firstpassword” and also the other account email2@example.com with password secondpassword
If you need to setup an email forwarding (email alias), you can do the following below [ Optional Step ]
INSERT INTO `mailserver`.`virtual_aliases` (`id`, `domain_id`, `source`, `destination`) VALUES (‘1′, ‘1’, ‘alias@example.com’, ‘email1@example.com’);
PostFix Setup
Open the postfix conf file
nano /etc/postfix/main.cf
Comment out the TLS parameters part ,your postfix should look same as the top
Copy and paste the following values into the config file below the TLS settings. This will ease the restrictions and allow users to send email from their home or office. By default, only users who are logged into the server locally are able to send email.
They will be required to log in with a password before able to send email.
The smtpd_sasl_type and smtpd_sasl_path lines tell Postfix to use Dovecot for user authentication. Dovecot already authenticates users checking their email, so it makes sense to have it handle outgoing authentication too.Next, you would need to change the following mydestination to localhost
mydestination = localhost
And also change the virtual transport value
virtual_transport = lmtp:unix:private/dovecot-lmtp
Make sure your setting is as followed below
Save the changes.
Next, we will create a file for the virtual domain records
nano /etc/postfix/mysql-virtual-mailbox-domains.cf
The mailuser and mailpass need change to the value of the MYSQL user and password that you create earlier on.
Save the change.
We test the postmap response, it should return 1. If not, its mean your setting went wrong.
postmap -q example.com mysql:/etc/postfix/mysql-virtual-mailbox-domains.cf
Next we edit the mailbox mapping config file
nano /etc/postfix/mysql-virtual-mailbox-maps.cf
Save the changes
Test Postfix to verify that it can find the first email address in your MySQL table. Enter the following command
postmap -q email1@example.com mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf
Next edit the alias config file
nano /etc/postfix/mysql-virtual-alias-maps.cf
Text postfix to verify it can find your first alias on the MYSQL table.
postmap -q alias@example.com mysql:/etc/postfix/mysql-virtual-alias-maps.cf
We will edit the master config file
nano /etc/postfix/master.cf
Locate and uncomment the two lines starting with submission and smtps. This will allow you to send mail securely on ports 587 and 465
Save the changes you’ve made to the /etc/postfix/master.cf file.
Do a restart of the postfix service
sudo service postfix restart
Dovecot
Now we begin the setup of Dovecot. Dovecot allows users to log in and check their email using POP3 and IMAP.
nano /etc/dovecot/dovecot.conf
Add the following line to /etc/dovecot/dovecot.conf so Dovecot knows to support IMAP, POP3, and LMTP.
Save your changes. We will begin edit the next config file
nano /etc/dovecot/conf.d/10-mail.conf
Uncomment mail_location line.
mail_location = maildir:/var/mail/vhosts/%d/%n
Find mail_priviledged_group and uncomment it, change it value
mail_privileged_group = mail
Save your changes, and next we create your mail folder.
mkdir -p /var/mail/vhosts/example.com
We create a user and add it to group 4000
groupadd -g 4000 vmail
useradd -g vmail -u 4000 vmail -d /var/mail
We change the permission of the folder of its owner to user vmail
chown -R vmail:vmail /var/mail
Next we edit the file /etc/dovecot/conf.d/10-auth.conf
nano /etc/dovecot/conf.d/10-auth.conf
We disable plaintext auth by uncomment this line
disable_plaintext_auth = yes
Change the auth mechanism
auth_mechanisms = plain login
Add a Hash Tag / Comment on the line below
#!include auth-system.conf.ext
Next we uncomment auth-sql.conf.ext and comment the rest as shown below.
Save your changes.
Next, we edit another config file
nano /etc/dovecot/conf.d/auth-sql.conf.ext
Paste the content below.
Save the changes and edit another config file
nano /etc/dovecot/dovecot-sql.conf.ext
Uncomment and set the value as mysql for driver
driver = mysql
Set the database connect line, change the mailuser and mailpass value to your database login credentials.
connect = host=127.0.0.1 dbname=mailserver user=mailuser password=mailpass
Uncomment the default pass scheme and change its value as below
default_pass_scheme = SHA512-CRYPT
Uncomment password query line and set as below
password_query = SELECT email as user, password FROM virtual_users WHERE email=’%u';
Save your changes.
Next change the permission of the folder
chown -R vmail:dovecot /etc/dovecot
chmod -R o-rwx /etc/dovecot
We will edit the socket information
nano /etc/dovecot/conf.d/10-master.conf
Save your changes and open the dovecot ssl config file next.
nano /etc/dovecot/conf.d/10-ssl.conf