How to Deploy a Mail Server with Webmail on Debian 12

Introduction

Setting up your own mail server can be a rewarding project, giving you full control over your email communications. This guide will walk you through deploying a mail server with webmail on Debian 12, ensuring you have a reliable and secure setup. We will use Postfix for the mail transfer agent (MTA), Dovecot for the mail delivery agent (MDA), and Roundcube for the webmail interface.

Prerequisites

Before we begin, ensure you have the following:

A fresh installation of Debian 12.
A domain name pointing to your server.
Basic knowledge of Linux command line.

Step 1: Update Your System

First, update your package lists and upgrade your system packages to ensure everything is up to date.

sudo apt update
sudo apt upgrade -y

Step 2: Install Postfix

Postfix is a widely-used MTA that will handle the sending and receiving of emails.

sudo apt install postfix -y

During the installation, you will be prompted to configure Postfix. Choose “Internet Site” and enter your domain name when asked.

Edit the Postfix configuration file to fine-tune settings:

sudo nano /etc/postfix/main.cf

Add or modify the following lines to match your domain:

myhostname = mail.yourdomain.com
mydomain = yourdomain.com
myorigin = $mydomain
inet_interfaces = all
inet_protocols = ipv4
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mynetworks = 127.0.0.0/8
home_mailbox = Maildir/

Restart Postfix to apply the changes:

sudo systemctl restart postfix

Step 3: Install Dovecot

Dovecot is the MDA that will handle the storage and retrieval of your emails.

sudo apt install dovecot-core dovecot-imapd dovecot-pop3d -y

Edit the Dovecot configuration file:

sudo nano /etc/dovecot/dovecot.conf

Ensure the following lines are included:

protocols = imap pop3 lmtp

Now, configure the mail directory and authentication:

sudo nano /etc/dovecot/conf.d/10-mail.conf

Set the mail location:

mail_location = maildir:~/Maildir

Configure authentication:

sudo nano /etc/dovecot/conf.d/10-auth.conf

Uncomment and modify the following lines:

disable_plaintext_auth = no
auth_mechanisms = plain login

Configure the user database:

sudo nano /etc/dovecot/conf.d/10-master.conf

Ensure the service auth section looks like this:

service auth {
  unix_listener /var/spool/postfix/private/auth {
    mode = 0666
    user = postfix
    group = postfix
  }
}

Restart Dovecot to apply the changes:

sudo systemctl restart dovecot

Step 4: Install Roundcube

Roundcube is a web-based IMAP client that provides a user-friendly interface for email.

First, install Apache, PHP, and the necessary PHP extensions:

sudo apt install apache2 php php-cli php-mbstring php-zip php-net-socket php-xml php-gd php-pear php-db php-mysql -y

Download and extract Roundcube:

cd /tmp
wget https://github.com/roundcube/roundcubemail/releases/download/1.6.1/roundcubemail-1.6.1-complete.tar.gz
tar -xvf roundcubemail-1.6.1-complete.tar.gz
sudo mv roundcubemail-1.6.1 /var/www/html/roundcube

Set the correct permissions:

sudo chown -R www-data:www-data /var/www/html/roundcube

Create a new database for Roundcube:

sudo mysql -u root -p

Within the MySQL prompt:

CREATE DATABASE roundcube;
CREATE USER 'roundcubeuser'@'localhost' IDENTIFIED BY 'yourpassword';
GRANT ALL PRIVILEGES ON roundcube.* TO 'roundcubeuser'@'localhost';
FLUSH PRIVILEGES;
EXIT;

Import the initial Roundcube database schema:

sudo mysql -u roundcubeuser -p roundcube < /var/www/html/roundcube/SQL/mysql.initial.sql

Configure Roundcube:

sudo cp /var/www/html/roundcube/config/config.inc.php.sample /var/www/html/roundcube/config/config.inc.php
sudo nano /var/www/html/roundcube/config/config.inc.php

Modify the following lines:

$config['db_dsnw'] = 'mysql://roundcubeuser:yourpassword@localhost/roundcube';
$config['default_host'] = 'ssl://localhost';
$config['smtp_server'] = 'localhost';
$config['smtp_user'] = '%u';
$config['smtp_pass'] = '%p';
$config['support_url'] = '';
$config['des_key'] = 'randomstring';
$config['plugins'] = array('archive', 'zipdownload');
$config['skin'] = 'elastic';

Restart Apache:

sudo systemctl restart apache2

Conclusion

You now have a fully functional mail server with a webmail interface on Debian 12. You can access Roundcube by navigating to http://yourdomain.com/roundcube in your web browser and logging in with your email credentials. Enjoy the control and flexibility of managing your own mail server!

LINUXexpert