Configure Postfix for emails

Project Discussion Landscape
1

These steps use SendGrid as an example email service provider that can be configured to work with Postfix. They may still generally apply to other email service providers, such as Mailjet, Amazon SES or Google.

Detailed information is available for Postfix in the Ubuntu Server documentation.

You can configure Postfix to handle your Landscape Server email notifications and alerts.

Set environment variables

To set the necessary environment variables, run the following code. Replace {API_KEY} with an API key from https://app.sendgrid.com/settings/api_keys:

SMTP_HOST='smtp.sendgrid.net'
SMTP_PORT='587'
SMTP_USERNAME='apikey'
SMTP_PASSWORD='{API_KEY}'

Install Postfix

To install Postfix, run:

sudo DEBIAN_FRONTEND=noninteractive apt-get install -y postfix

Use Postconf to configure the /etc/postfix/main.cf file

  1. Configure the /etc/postfix/main.cf file with Postconf:

    sudo postconf -e myhostname="$FQDN"
sudo postconf -e mydomain="$DOMAIN"
sudo postconf -e myorigin="$DOMAIN"
sudo postconf -e masquerade_domains="$DOMAIN"
sudo postconf -e mydestination=localhost
sudo postconf -e default_transport=smtp
sudo postconf -e relay_transport=smtp
sudo postconf -e relayhost="[${SMTP_HOST}]:${SMTP_PORT}"
sudo postconf -e smtp_sasl_auth_enable=yes
sudo postconf -e smtp_sasl_password_maps=hash:/etc/postfix/sasl_passwd
sudo postconf -e smtp_sasl_security_options=noanonymous
sudo postconf -e header_size_limit=4096000

    This code block includes the following values that must be changed:

    {SMTP_HOST}: The hostname or IP address of the SMTP server to which Postfix will relay outgoing emails

    {SMTP_PORT}: The port number on which the SMTP server is listening for incoming connections

  2. SendGrid requires TLS encryption when connecting on Port 587, so you must make the following additional configurations:

    sudo postconf -e smtp_use_tls=yes
sudo postconf -e smtp_tls_security_level=encrypt
sudo postconf -e smtp_sasl_tls_security_options=noanonymous

Finish configuration

  1. Write /etc/postfix/sasl_passwd with the authentication credentials:

    sudo sh -c "echo \"[$SMTP_HOST]:$SMTP_PORT $SMTP_USERNAME:$SMTP_PASSWORD\" > /etc/postfix/sasl_passwd"

  2. Generate a hashed version of that file:

    sudo postmap /etc/postfix/sasl_passwd

  3. Secure /etc/postfix/sasl_passwd.db:

    sudo chmod 600 /etc/postfix/sasl_passwd.db

  4. Remove /etc/postfix/sasl_passwd for security:

    sudo rm /etc/postfix/sasl_passwd

  5. Restart Postfix for these settings to take effect:

    sudo /etc/init.d/postfix restart

(Optional) Add an email alias

To ensure that important system emails get attention, we recommend adding an alias for Landscape on your local environment.

  1. Open the aliases file:

    sudo vim /etc/aliases

  2. Add the Landscape alias, replacing <RECIPIENT_EMAIL> with the email where Landscape notifications should be sent:

     landscape: <RECIPIENT_EMAIL>

  3. Rebuild your aliases:

    sudo /usr/bin/newaliases