How to Setup a Complete Mail Server (Postfix) using ‘Roundcube’ (Webmail) on Ubuntu/Debian

Creating a mail server on Linux powered machines can be one of the most essential things that every system administrator needs to do while configuring the servers for the first time, if you don’t know what it means; it’s simple, if you have a website like “”, you can create an email account like “[email protected]” to use it to send/receive emails easily instead of using services like Hotmail, Gmail, Yahoo Mail, etc.

In this article, we’ll learn how to do so by installing the Postfix mail server with the “Roundcube” webmail application and its dependencies on Debian 10/9 and Ubuntu 20.04/18.04/16.04 LTS releases.

Step 1: Set a Hostname and Create DNS Records for Domain

1. First, set a valid FQDN (Fully Qualified Domain Name) hostname for your Ubuntu server using the hostnamectl command as shown.

$ sudo hostnamectl set-hostname

2. Next, you need to add a MX and A records for your domain in your DNS control panel that guides other MTAs that your mail server domain is responsible for email delivery.

MX record    @         <IP-address>

Step 2: Installing Apache, MariaDB, and PHP on Ubuntu

3. In order to create a running mail server using “Roundcube”, we’ll have to install Apache2, MariaDB, and PHP packages first, to do so, run.

$ sudo apt-get update -y
$ sudo apt-get upgrade -y
$ sudo apt install apache2 apache2-utils mariadb-server mariadb-client php7.4 libapache2-mod-php7.4 php7.4-mysql php-net-ldap2 php-net-ldap3 php-imagick php7.4-common php7.4-gd php7.4-imap php7.4-json php7.4-curl php7.4-zip php7.4-xml php7.4-mbstring php7.4-bz2 php7.4-intl php7.4-gmp php-net-smtp php-mail-mime php-net-idna2 mailutils

On Debian 10/9, you need to download and install the SURY PHP PPA repository to install PHP 7.4 on Debian 10/9 as shown.

$ sudo apt -y install lsb-release apt-transport-https ca-certificates 
$ sudo wget -O /etc/apt/trusted.gpg.d/php.gpg
$ echo "deb $(lsb_release -sc) main" | sudo tee /etc/apt/sources.list.d/php.list
$ sudo apt update
$ sudo apt install apache2 apache2-utils mariadb-server mariadb-client php7.4 libapache2-mod-php7.4 php7.4-mysql php-net-ldap2 php-net-ldap3 php-imagick php7.4-common php7.4-gd php7.4-imap php7.4-json php7.4-curl php7.4-zip php7.4-xml php7.4-mbstring php7.4-bz2 php7.4-intl php7.4-gmp php-net-smtp php-mail-mime php-net-idna2 mailutils

Step 3: Installing Postfix Mail Server on Ubuntu

4. Postfix is a mail transfer agent (MTA) which is the responsible software for delivering & receiving emails, it’s essential in order to create a complete mail server.

To install it on Ubuntu/Debian or even Mint, run:

$ sudo apt-get install postfix

During installation, you will be asked to choose the type of mail configuration, choose “Internet Site”.

Install Postfix in Ubuntu
Install Postfix in Ubuntu

5. Now enter the fully qualified domain name that you want to use for send and receive emails.

Set Postfix Mail Domain
Set Postfix Mail Domain

6. Once Postfix installed, it will automatically start and creates a new /etc/postfix/ file. You can verify the Postfix version and status of the service using the following commands.

$ postconf mail_version
$ sudo systemctl status postfix
Check Postfix Version
Check Postfix Version

Step 4: Testing Postfix Mail Server on Ubuntu

7. Now try to check your mail server is connecting on port 25 using the following command.

$ telnet 25

Connected to
Escape character is '^]'.
220 ESMTP k12si849250plk.430 - gsmtp

The above message indicates that the connection is successfully established. Type quit to close the connection.

8. You can also use a mail program to send and read emails using the following command.

$ mail [email protected]

Subject: Testing My Postfix Mail Server
I'm sending this email using the postfix mail server from Ubuntu machine

Step 5: Installing Dovecot IMAP and POP in Ubuntu

9. Dovecot is a mail delivery agent (MDA), it delivers the emails from/to the mail server, to install it, run the following command.

$ sudo apt-get install dovecot-imapd dovecot-pop3d
Install Dovecot in Ubuntu
Install Dovecot in Ubuntu

10. Next, restart the Dovecot service using the following command.

$ sudo systemctl restart dovecot
$ sudo service dovecot restart
Start Dovecot in Ubuntu
Start Dovecot in Ubuntu

Step 6: Installing Roundcube Webmail in Ubuntu

11. Roundcube is the webmail server that you’ll be using to manage emails on your server, it has a simple web interface to do the job, it can be customized by installing more modules & themes.

$ wget
$ tar -xvf roundcubemail-1.4.8.tar.gz
$ sudo mv roundcubemail-1.4.8 /var/www/html/roundcubemail
$ sudo chown -R www-data:www-data /var/www/html/roundcubemail/
$ sudo chmod 755 -R /var/www/html/roundcubemail/

12. Next, you need to create a new database and user for Roundcube and grant all permission to a new user to write to the database.

$ sudo mysql -u root
MariaDB [(none)]> CREATE DATABASE roundcube DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
MariaDB [(none)]> CREATE USER [email protected] IDENTIFIED BY 'password';
MariaDB [(none)]> GRANT ALL PRIVILEGES ON roundcube.* TO [email protected];
MariaDB [(none)]> flush privileges;
MariaDB [(none)]> quit;

13. Next, import the initial tables to the Roundcube database.

$ sudo mysql roundcube < /var/www/html/roundcubemail/SQL/mysql.initial.sql

Step 7: Create an Apache Virtual Host for Roundcube Webmail

14. Create an apache virtual host for Roundcube webmail.

$ sudo nano /etc/apache2/sites-available/roundcube.conf

Add the following configuration in it.

<VirtualHost *:80>
  DocumentRoot /var/www/html/roundcubemail/

  ErrorLog ${APACHE_LOG_DIR}/roundcube_error.log
  CustomLog ${APACHE_LOG_DIR}/roundcube_access.log combined

  <Directory />
    Options FollowSymLinks
    AllowOverride All

  <Directory /var/www/html/roundcubemail/>
    Options FollowSymLinks MultiViews
    AllowOverride All
    Order allow,deny
    allow from all


15. Next, enable this virtual host and reload the apache for the changes.

$ sudo a2ensite roundcube.conf
$ sudo systemctl reload apache2

16. You can now access the webmail by going to

Roundcube Webmail Installer
Roundcube Webmail Installer

16. Next, go to the Database settings and add the database details.

Roundcube Webmail Database Settings
Roundcube Webmail Database Settings

17. After making all the changes, create a file.

Create Roundcube Configuration File
Create Roundcube Configuration File

18. After finishing the installation and the final tests please delete the installer folder and make sure that enable_installer option in is disabled.

$ sudo rm /var/www/html/roundcubemail/installer/ -r

19. Now go to the login page and enter the user name and the password of the user.
Roundcube Webmail Login
Roundcube Webmail Login

Step 8: Creating Mail Users

20. In order to start using the Roundcube webmail, you’ll have to create a new user, to do so, run.

$ sudo useradd myusername

Replace “myusername” with the user name you want, create a password for the new user by running.

$ sudo passwd myusername

21. Now go back to the login page and enter the user name and the password of the newly created user.

Have you tried to create an email server before? How did it go? Have you used Roundcube or any other mail server before? What do you think about it?

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272 thoughts on “How to Setup a Complete Mail Server (Postfix) using ‘Roundcube’ (Webmail) on Ubuntu/Debian”

  1. Just in case people come across problem-related to packages php not loading, I had to install


    over php7.4 to make it working.

    sample error logs:

    PHP Fatal error: Uncaught Error: Class ‘PEAR’ not found in /var/www/html/roundcubemail/program/lib/Roundcube/bootstrap.php:103\nStack trace:\n#0 /var/www/html/roundcubemail/program/include/iniset.php(62): require_once()\n#1 /var/www/html/roundcubemail/installer/index.php(43): require(‘/var/www/html/r…’)\n#2 {main}\n thrown in /var/www/html/roundcubemail/program/lib/Roundcube/bootstrap.php on line 103

    • @Fandi,

      Check Port 25 is opened on your UFW firewall and also make sure that port 25 listening on the TCP socket using the netstat command.

  2. Wow, this article just popped up in my RSS reader today.

    Why on earth SquirrelMail? I have used it 14 yrs ago on my 50MB webspace, but it seems like since then it has not evolved – besides security fixes – at all.

    It might still work just good enough for its purpose, but I think there are a couple of modern alternatives…

      • I don’t know for sure that development has “stopped”.
        I thought it still is maintained for security patches.

        But take a look at its homepage, it has barely seen updates in the last 5-6 yrs.

        TIA for updating. I also use Roundcube, it’s a good alternative!

  3. I have this problem:

    ERROR: Config file ‘. ‘”config/config.php” not found. You need to ‘ . ‘configure SquirrelMail before you can use it.
    ‘; exit; } // If we are, go ahead to the login page. header(‘Location: src/login.php’); ?>

    Run ./configure and can’t access

  4. Hey, great tutorial. I had some problems at the end though.

    If anyone is having the same problem on an Apache2 server, of www-data not being able to write to /var/local/squirrelmail/data you have to create the directories, use chown to give it to www-data and give it write permissions with chmod.

  5. I am getting this error on my apache2 php7.3:- Warning: session_set_cookie_params(): Cannot change session cookie parameters when session is active in /var/www/html/squirrelmail/functions/global.php on line 472.

    Any solution??

  6. I can’t access the, I have already made sure that everything was correct and as it is. Please help me and contact me on my email if you are willing to help. this is for my final project.


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