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

  1. I have configured almost everything and also the mail is working perfectly fine but my question is can’t we install squirrel administrator for managing all the users using web ui ?

    • Hello, @Sushant

      Based on my previous setup of email servers through this tutorial. I haven’t found any web UI for managing squirrel mail users.

      What I done is build a simple web UI and API using nodejs for CRUD users.

  2. Hi,

    Many thanks for sharing this article.

    However, my major problem is how to point the dns to enable it work. For example, i purchased my domain from, what configuration must i do at the domain provider’s site?
    And, how can I set up the following:


    I have an account with, where I have also created a droplet and have an IP for my domain. I have created a new record at and I have changed the dns server information at as and

    I have already setup Postfix Mail Server on my Ubuntu 14, although, without installing the squirrel mail, but while i was researching how to fix the above, i came across this post and i find it very helpful because I was able to add Squirrel Mail to my Postfix Mail, but still, nothing is working.

    Please I really need your help to fix this.

  3. Hi ,

    When I try to send any mail I got an error like:

    “Service not available, closing channel
    421 4.3.0 collect: Cannot write ./dfwAKAhJ3f108965 (bfcommit, uid=0, gid=119): No such file or directory”

    Is there anybody give me a hand to rid out of it .


  4. Hi Zac, I still have the error even though I added my user to the mail group. From my /var/llog/mail.err, I am getting this:

    localhost dovecot: imap(myusername): Error: Opening INBOX failed: Mailbox isn’t selectable

  5. Hello

    During the installation of Dovecot did not execute the creation of SSL keys, how do I create at this time?

    Another thing, following step by step, I still have a problem logging in to squirrelmail: ERROR: Connection dropped by IMAP server.

    Can you help me?

    Thank you.


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