How to Setup a Complete Mail Server (Postfix) using ‘SquirrelMail’ (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 his 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.

Setup Postfix Mail Server in Debian

Setup Postfix Mail Server in Ubuntu/Debian

In this article, we’ll learn how to do so by installing the Postfix with “SquirrelMail” webmail application and its dependencies on Debian/Ubuntu machines.

Step 1: Installing Apache2 and PHP7

1. In order to create a running mail server using “SquirrelMail”, we’ll have to install both Apache2 & PHP7 packages first, to do so, run.

$ sudo apt-get update -y
$ sudo apt-get upgrade -y
$ sudo apt-get install apache2 php7
Install Apache and PHP

Install Apache and PHP

Step 2: Installing Postfix Mail Server

2. 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

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

Set Postfix Mail Domain

Set Postfix Mail Domain

4. Once the FQDN set, you’ve restart the Postfix mail server using.

$ sudo service postfix restart
Start Postfix Mail Server in Ubuntu

Start Postfix Mail Server in Ubuntu

Step 3: Installing Dovecot

5. 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

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

$ sudo service dovecot restart
Start Dovecot in Ubuntu

Start Dovecot in Ubuntu

Step 4: Installing SquirrelMail in Ubuntu

7. SquirrelMail is the email 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
$ unzip
$ sudo mv squirrelmail-webmail-1.4.22 /var/www/html/
$ sudo chown -R www-data:www-data /var/www/html/squirrelmail-webmail-1.4.22/
$ sudo chmod 755 -R /var/www/html/squirrelmail-webmail-1.4.22/
$ sudo mv /var/www/html/squirrelmail-webmail-1.4.22/ /var/www/html/squirrelmail

8. After the installation, you will have to run this command in order to configure SquirrelMail.

$ sudo perl /var/www/html/squirrelmail/config/
Configure Squirrelmail in Ubuntu

Configure Squirrelmail in Ubuntu

09. Next, enter “2” in order to edit the server settings, and you will be prompted to it.

Squirrelmail Server Settings

Squirrelmail Server Settings

10. Now enter “1” in order to change the domain name and write up your domain (e.g:

Set Mail Domain

Set Mail Domain

11. Go back to the main menu by writing “R” and hitting the enter key, write “4” in order to configure the general options.

You see “Allow server-side sorting”? Enter “11” and change it from “false” to “true” by entering “y”. Now hit the Enter key, and enter the “S” key in order to save the configuration file.

Configure General Mail Options

Configure General Mail Options

12. You can now access the mail server by going to

Access Squirrelmail in Ubuntu

Access Squirrelmail

Step 5: Creating Mail Users

13. In order to start using squirrelmail 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

14. Create a home folder for the user in /var/www/html/myusername and make it default home directory.

$ sudo mkdir -p /var/www/html/myusername
$ usermod -m -d /var/www/html/myusername myusername

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

Access Squirrelmail in Ubuntu

Access Squirrelmail

You will be surprise to see the following error message.

Login to Squirrelmail

Login to Squirrelmail

This is just a problem in the permissions, you have to give the user “myusername” the complete permissions on its home folder.

$ sudo chown -R myusername:myusername /var/www/html/myusername

16. Once permission set, you should able to login into squirrelmail.

Squirrelmail Mail Interface

Squirrelmail Mail Interface

You can try to send email from it, or you can try to receive emails by sending it to “[email protected]” , don’t forget to replace “myusername” with the user name you created.

If you faced any other error.. Just check the “/var/log/mail.err” file, all the error message will be stored there, you won’t lose your way :)

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

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Aaron Kili

Aaron Kili is a Linux and F.O.S.S enthusiast, an upcoming Linux SysAdmin, web developer, and currently a content creator for TecMint who loves working with computers and strongly believes in sharing knowledge.

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241 Responses

  1. Anonymous says:

    You should install this package to allow PHP to interface with apache2:


    Do not forget to edit the dir.conf file to make .php have higher precedence than .html so that the mail server works. Afterward restart the server and it should work

  2. Alex says:

    Loggin in with the user account is not a good idea tho. Most server configuration files can be read by all user and some of WordPress files can be written by all users (not by default). Your server will be vulnerable if one of your user accounts is exposed. It is better to use database based mail user account

  3. Jaro says:

    I can receive emails but no one receives mine…

    • Jaro says:

      Got this message:

      This is the mail system at host [DOMAIN].

      I’m sorry to have to inform you that your message could not
      be delivered to one or more recipients. It’s attached below.

      For further assistance, please send mail to postmaster.

      If you do so, please include this problem report. You can
      delete your own text from the attached returned message.

      The mail system

      : host[2a00:1450:400c:c01::1b] said: 550-5.7.1
      [2a02:c205:3002:4898::1] Our system has detected that this message
      550-5.7.1 does not meet IPv6 sending guidelines regarding PTR records and
      550-5.7.1 authentication. Please review 550-5.7.1 for more information 550
      5.7.1 . d14si1503938wrn.307 – gsmtp (in reply to end of DATA command)

  4. gamalo says:

    Hi, first and foremost, this is a great page; I’m stuck in step 4.12 (installing SquirrelMail-access the webserver (login page)) because I’m getting the PHP code (plain text) instead of the login page in my browser.

    I’m running an ubuntu 16.04 server and I will appreciate any help to fix this issue.

  5. Katumba says:

    Hello there, I’m trying to set up my email, but when I try to log in, I get an error as below.

    Error opening ../data/default_pref
    Could not create an initial preference file!
    /var/local/squirrelmail/data/ should be writable by user www-data
    Please contact your system administrator and report this error.

    What should I do?

    • Ravi Saive says:


      Make the following directory writable by user www-data.

      $ sudo chown -R www-data:www-data /var/local/squirrelmail/data/
      $ sudo chmod -R 776 /var/local/squirrelmail/data/
  6. MM says:

    I had an issue like “Error opening ../config/default_pref

    Could not create initial preference file!
    /var/lib/squirrelmail/data/ should be writable by user www-data
    Please contact your system administrator and report this error.”

    I could fix it by changing the Data Directory in the General Options to /var/www/html/squirrelmail/data.

    Hope this helps somebody

    • Ravi Saive says:


      Make the following directory writable by user www-data.

      $ sudo chown -R www-data:www-data /var/local/squirrelmail/data/
      $ sudo chmod -R 776 /var/local/squirrelmail/data/
  7. Adnan says:

    I work on my client’s Linux servers, and I found your article useful for me. I had permission issues though with the mail server but finally fixed it.

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