Configuring Postfix to Send Email via Simple Email Service (SES)

1. Install and Configure Postfix

Ensure that Postfix is installed on your server. If not, you can install it using your package manager. On Ubuntu, you can install Postfix with:

sudo apt-get update
sudo apt-get install postfix

During installation, you may be prompted to choose a mail server configuration. Select “Internet Site” and enter your server’s domain name when prompted.

2. Configure Relayhost

Open the Postfix main configuration file /etc/postfix/main.cf in a text editor:

sudo nano /etc/postfix/main.cf

Add or modify the relayhost parameter to specify the SES SMTP endpoint. For example:

relayhost = email-smtp.us-west-2.amazonaws.com:587

Replace email-smtp.us-west-2.amazonaws.com with the SES SMTP endpoint for your region. Ensure you use the appropriate port (typically 587 for TLS encryption).

3. Authentication

If your SES SMTP endpoint requires authentication (which is likely), you’ll need to provide credentials. Add the following lines to your main.cf:

smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_security_level = encrypt

Create a file /etc/postfix/sasl_passwd and add your SES SMTP credentials in the following format:

email-smtp.us-west-2.amazonaws.com:587 SES_SMTP_USERNAME:SES_SMTP_PASSWORD

Replace SES_SMTP_USERNAME and SES_SMTP_PASSWORD with your SES SMTP username and password.

Secure the file with appropriate permissions:

sudo chmod 600 /etc/postfix/sasl_passwd

Finally, generate the Postfix lookup table for the SASL password file:

sudo postmap /etc/postfix/sasl_passwd

4. Restart Postfix

After making these changes, restart the Postfix service to apply the configuration:

sudo systemctl restart postfix

When setting up Postfix within an ISPConfig environment on Ubuntu 22, configuring it to send emails via Simple Email Service (SES) requires a few steps. After installing and configuring ISPConfig, proceed to configure Postfix by specifying SES as the relay host in the main configuration file. Ensure to provide SES SMTP credentials for authentication and secure them appropriately. Once configured, restart the Postfix service to apply the changes. This integration ensures that Postfix, within the ISPConfig setup, leverages SES for reliable email delivery