Many Ubuntu users use the system not only for home needs. This approach is fully justified, because on Linux-systems it is much more convenient to do programming, creating servers and websites. One of the conveniences is the creation of an email server. For beginners, this task will seem terribly difficult, but if you figure out how to install and configure the mail server for Ubuntu, the task will not seem so hard for you.
How to set up a mail server based on Ubuntu.
A bit of theory
Before specific instructions and fermentation of the code can not do without a fraction of theoretical material. It is important to understand what an email server is and how it works.
A configured mail server, to put it very simply, is a postman who receives a “letter” from one email client and gives it to another. In this, in principle, the whole essence of the work of this software. The mail server is needed not only for sending email. On the sites, he is responsible for registering users, submitting forms and other important actions, without which the site would become like a book, which you can only look at by turning the pages, but it is difficult to do something.
Mail servers on Linux are significantly different from those on Windows and other systems. On Windows, this is a ready-made closed program, which can only start to use. Linux distributions also require self-tuning of all components. And the server will eventually consist of not one program, but several. We will use Postfix in combination with Dovecot and MySQL.
Why Postfix?
There are several email clients on Ubuntu, but we still chose this one. Setting up Posfix on Ubuntu is much easier than the same SendMail, and this is important for a novice user. In combination with Dovecot, Postfix is able to do everything that is usually required from mail servers.
Postfix is directly the mail transfer agent itself. He will play a major role in the whole submission. This is an open source program that many servers and websites use by default. Dovecot is a mail delivery agent. Its main role is to ensure server security. MySQL is an ideal database management system (DBMS) for any sites. It is needed to handle the information we receive from users of our server.
So, with the theoretical part is over. Now it is worth going to practice.
Create mail server
What should be configured before installing the mail server?
- MySQL;
- DNS zone, you must have a personal FDQN. Next we will use namehost.
Installation
Install the program:
apt-get install postfix postfix-mysql dovecot-core dovecot-imapd dovecot-lmtpd dovecot-mysql
When the Postfix configuration window appears, we will need to select the “Internet site”.
Below we will be asked to enter a domain name, use "primer.ru".
MySQL setup
Now we need to configure three tables for data in MySQL: for domains, users, and for so-called Alias — aliases or additional user mailboxes. Here we will not discuss in detail the configuration of the MySQL database.
Let's call the examplemail database. Create a database with the following name:
mysqladmin -p create servermail
Login in MySQL:
mysql -u root –p
Then enter the password. If everything is done correctly, there will be an entry in the terminal:
mysql>
Create a new user specifically to log into the network:
mysql> GRANT SELECT ON examplemail. * TO 'usermail'@'127.0.0.1' IDENTIFIED BY 'password';
Now restart MySQL to make sure all changes are applied successfully.
We use our database to create tables based on it:
mysql> USE examplemail;
Create a table for domains:
CREATE TABLE `virtual_domains` (
`id` INT NOT NULL AUTO_INCREMENT,
`name` VARCHAR (50) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE = InnoDB DEFAULT CHARSET = utf8;
Create a table for users:
CREATE TABLE `virtual_users` (
`id` INT NOT NULL AUTO_INCREMENT,
`domain_id` INT NOT NULL,
`password` VARCHAR (106) NOT NULL,
`email` VARCHAR (120) 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;
Here, as you can see, added email and password. And each user is bound to the domain.
Finally, create a table for pseudonyms:
CREATE TABLE `virtual_aliases` (
`id` INT NOT NULL AUTO_INCREMENT,
`domain_id` INT 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;
We have successfully configured MySQL and created three necessary tables. Now you need to deal with domains and emails.
Domains, email addresses and aliases
Let's add our domain to the table with domains. FDQN must be entered there:
INSERT INTO `examplemail`.`virtual_domains`
(`id`, ` name`)
VALUES
('1', 'example.com'),
('2', 'namehost.example.com');
Add data about the email address to the user table:
INSERT INTO `examplemail`.`virtual_users`
(`id`, ` domain_id`, `password`, ` email`)
VALUES
('1', '1', ENCRYPT ('firstpassword', CONCAT ('$ 6 $', SUBSTRING (SHA (RAND ()), -16))), ' '),
('2', '1', ENCRYPT ('secondpassword', CONCAT ('$ 6 $', SUBSTRING (SHA (RAND ()), -16))), ' ');
Now add the information to the last table:
INSERT INTO `examplemail`.`virtual_aliases`
(`id`, ` domain_id`, `source`, ` destination`)
VALUES
('1', '1', ' ', ' ');
Close MySQL:
mysql> exit
Postfix Setup
Moving directly to the parameters Postfix. We need the mail client to send messages on behalf of the users entered into the database and handle the SMTP connection. To begin with, we will create a backup of the configuration file, in which case it was possible to return to the default settings:
cp /etc/postfix/main.cf /etc/postfix/main.cf.orig
Now open the configuration file:
nano /etc/postfix/main.cf
Instead of nano, you can use any text editor that is convenient for you.
We will comment out the TLS parameters, and also add others. Free SSL is used here:
# TLS parameters
# smtpd_tls_cert_file = / etc / ssl / certs / ssl-cert-snakeoil.pem
# smtpd_tls_key_file = / etc / ssl / private / ssl-cert-snakeoil.key
# smtpd_use_tls = yes
#smtpd_tls_session_cache_database = btree: $ {data_directory} / smtpd_scache
#smtp_tls_session_cache_database = btree: $ {data_directory} / smtp_scache
smtpd_tls_cert_file = / etc / ssl / certs / dovecot.pem
smtpd_tls_key_file = / etc / ssl / private / dovecot.pem
smtpd_use_tls = yes
smtpd_tls_auth_only = yes
After that we will add some more parameters:
smtpd_sasl_type = dovecot
smtpd_sasl_path = private / auth
smtpd_sasl_auth_enable = yes
smtpd_recipient_restrictions =
permit_sasl_authenticated,
permit_mynetworks
reject_unauth_destination
We also need to comment out the mydestination settings and change them to localhost:
#mydestination = example.com, namehost.example.com, localhost.example.com, localhost
mydestination = localhost
The myhostname parameter should contain our domain name:
myhostname = namehost.example.com
Now add a line to send messages to all domains listed in the MySQL table:
virtual_transport = lmtp: unix: private / dovecot-lmtp
Add three more parameters so that Postfix can connect to MySQL tables:
virtual_mailbox_domains = mysql: /etc/postfix/mysql-virtual-mailbox-domains.cf
virtual_mailbox_maps = mysql: /etc/postfix/mysql-virtual-mailbox-maps.cf
virtual_alias_maps = mysql: /etc/postfix/mysql-virtual-alias-maps.cf
Setting up MySQL and Postfix files
Create a file
mysql-virtual-mailbox-domains.cf
Add these values to it:
user = usermail
password = mailpassword
hosts = 127.0.0.1
dbname = examplemail
query = SELECT 1 FROM virtual_domains WHERE name = '% s'
Restart Postfix:
service postfix restart
Test domain for Postfix:
postmap -q example.com mysql: /etc/postfix/mysql-virtual-mailbox-domains.cf
Create another file:
nano /etc/postfix/mysql-virtual-mailbox-maps.cf
user = usermail
password = mailpassword
hosts = 127.0.0.1
dbname = examplemail
query = SELECT 1 FROM virtual_users WHERE email = '% s'
Reboot Postfix:
service postfix restart
Then check Postfix again:
postmap -q mysql: /etc/postfix/mysql-virtual-mailbox-maps.cf
If done correctly, should be displayed
Create the last file for aliases:
nano /etc/postfix/mysql-virtual-alias-maps.cf
user = usermail
password = mailpassword
hosts = 127.0.0.1
dbname = examplemail
query = SELECT destination FROM virtual_aliases WHERE source = '% s'
Restart:
service postfix restart
Last time we test:
postmap -q mysql: /etc/postfix/mysql-virtual-alias-maps.cf
Dovecot setup
We make backups for seven files that will be changed:
cp /etc/dovecot/dovecot.conf /etc/dovecot/dovecot.conf.orig
This is a sample command. Enter six more of the same for these files:
/etc/dovecot/conf.d/10-mail.conf
/etc/dovecot/conf.d/10-auth.conf
/etc/dovecot/dovecot-sql.conf.ext
/etc/dovecot/conf.d/10-master.conf
/etc/dovecot/conf.d/10-ssl.conf
Open the first file:
nano /etc/dovecot/dovecot.conf
Check if this parameter is commented out:
! include conf.d / *. conf
Enter:
! include_try /usr/share/dovecot/protocols.d/*.protocol
protocol = imap lmtp
Instead:
! include_try /usr/share/dovecot/protocols.d/*.protocol line
Edit the following file:
nano /etc/dovecot/conf.d/10-mail.conf
Find the line mail_location, remove the comment, set the following parameter:
mail_location = maildir: / var / mail / vhosts /% d /% n
Find mail_privileged_group, put there:
mail_privileged_group = mail
We check access. Enter the command:
ls -ld / var / mail
Access should look like this:
drwxrwsr-x 3 root vmail 4096 Jan 24 21:23 / var / mail
Create a folder for each registered domain:
mkdir -p /var/mail/vhosts/example.com
Create a user and group with ID 5000:
groupadd -g 5000 vmail
useradd -g vmail -u 5000 vmail -d / var / mail
Change the owner to the user VMail:
chown -R vmail: vmail / var / mail
Edit the following file:
nano /etc/dovecot/conf.d/10-auth.conf
Uncomment the authentication text and add the line:
disable_plaintext_auth = yes
Change the following parameter:
auth_mechanisms = plain login
Commenting on this line:
#! include auth-system.conf.ext
Add MySQL authorization, comment out the line:
! include auth-sql.conf.ext
Create a file with data for authentication:
nano /etc/dovecot/conf.d/auth-sql.conf.ext
Enter there the following:
passdb {
driver = sql
args = /etc/dovecot/dovecot-sql.conf.ext
}
userdb {
driver = static
args = uid = vmail gid = vmail home = / var / mail / vhosts /% d /% n
}
Edit the following file:
nano /etc/dovecot/dovecot-sql.conf.ext
Set the MySQL parameter and comment out:
driver = mysql
Uncomment and enter:
connect = host = 127.0.0.1 dbname = servermail user = usermail password = mailpassword
Find the line default_pass_scheme, uncomment and enter the parameter:
default_pass_scheme = SHA512-CRYPT
Uncomment and introduce a new parameter:
password_query = SELECT email as user, password FROM virtual_users WHERE email = '% u';
Change the owner:
chown -R vmail: dovecot / etc / dovecot
chmod -R o-rwx / etc / dovecot
Open and edit the file:
nano /etc/dovecot/conf.d/10-master.conf
Uncomment and enter the parameter:
service imap-login {
inet_listener imap {
port = 0
}
Enter:
service lmtp {
unix_listener / var / spool / postfix / private / dovecot-lmtp {
mode = 0600
user = postfix
group = postfix
}
#inet_listener lmtp {
# Avoid making LMTP visible for the internet
#address =
#port =
#}
}
Change the following configuration:
service auth {
unix_listener / var / spool / postfix / private / auth {
mode = 0666
user = postfix
group = postfix
}
unix_listener auth-userdb {
mode = 0600
user = vmail
#group =
}
#unix_listener / var / spool / postfix / private / auth {
# mode = 0666
#}
user = dovecot
}
Change the last configuration in this file:
service auth-worker {
# Auth worker process
# / etc / shadow. If this isn’t necessary
# $ default_internal_user.
user = vmail
}
So, we finally set up a mail server on Ubuntu. And you can also add an SSL configuration there or use the default one. To protect against spam, you can configure Spam Assassin to work with our server.
Use the standard email client to enter this information:
- Username:
- Password: email1
- IMAP: example.com
- SMTP: example.com