How To Install and Setup Postfix on Ubuntu 12.04

Status: Deprecated #

This article covers a version of Ubuntu that is no longer supported. If you are currently operate a server running Ubuntu 12.04, we highly recommend upgrading or migrating to a supported version of Ubuntu:

Upgrade to Ubuntu 14.04.
Upgrade from Ubuntu 14.04 to Ubuntu 16.04
Migrate the server data to a supported version

Reason:
Ubuntu 12.04 reached end of life (EOL) on April 28, 2017 and no longer receives security patches or updates. This guide is no longer maintained.
See Instead:
This guide might still be useful as a reference, but may not work on other Ubuntu releases. If available, we strongly recommend using a guide written for the version of Ubuntu you are using. You can use the search functionality at the top of the page to find a more recent version.

About Postfix #

Postfix is a free, open source Mail Transfer Agent which works to route and deliver email. 

Prerequisites #

Before installing Postfix, you will need to have a Fully Qualified Domain Name pointing to the server that you will be using.
You can find instructions on that here:How to Set Up a Host Name with DigitalOcean

Install Postfix #

Postfix can easily be installed through apt-get:

sudo apt-get install postfix

During the installation, you will see a dialogue box appear, asking you which kind of installation you would prefer. Select “Internet Site”.
Follow up by entering the name of your domain.
Once Postfix is installed there are a few steps that need to be taken before it is fully functional.

Configure Postfix #

Once Postfix is installed, go ahead and open the main configuration file.

sudo nano /etc/postfix/main.cf

There are a few changes that should be made in this file.

myhostname = example.com

Put in name of your domain into myhostname.
If you want to have mail forwarded to other domains, replace alias_maps with virtual_alias_maps and point it to /etc/postfix/virtual.

virtual_alias_maps = hash:/etc/postfix/virtual

The rest of the entries are described below
mydestination defines the domains that postfix is going to serve, in this case—localhost and your domain (eg. example.com).
relayhost can be left, as is the default, empty.
mynetworks defines who can use the mail server. This should be set to local—creating an open mail server is asking for SPAM. This will usually have damaging effects on your server and may put you in line for discipline from your web hosting provider.
If it is not set up by default, as it should be, make sure you have the following text on that line:

mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

The rest of the lines are set by default. Save, exit, and reload the configuration file to put your changes into effect:

sudo /etc/init.d/postfix reload

Configure Additional Emails #

To redirect emails to specific emails, you can add users to the alias file. By default each user on the server will be able to read emails directed to their username@domain-name.com.
Open up the the alias database:

sudo nano /etc/postfix/virtual

Within that file, enter in the names of your users. For example:

sales@example.com username1
me@example.com username2

Once you are finished, save, exit, and run the following command:

postmap /etc/postfix/virtual

The last step is to reload postfix once more.

sudo /etc/init.d/postfix reload

Conclusion #

Once Postfix is installed, mail can be sent to and from the server, although without a mail server like Dovecot or Cyrus, you will only be able to see the email on the server.
You send out email from the command line with the command “sendmail” and where you want the mail sent to:

sendmail sample-email@example.org

Once you enter the command, type your message, and when it is completed, you can send it off with ctrl-D
Incoming mail gets delivered into /var/mail/username
By Etel Sverdlov