Setting Up Postfix for SMTP

Install and Configure Postfix

Install Postfix

sudo apt update
sudo apt install postfix -y

Configure Postfix

Edit the Postfix main configuration file:

sudo nano /etc/postfix/main.cf

Add or modify the following configurations:

relayhost = [smtp.example.in]:1025  # Specify your SMTP relay host and port
# Add user and password variables if needed

Restart Postfix to Apply Changes
```
sudo systemctl restart postfix
```

Test Email Functionality

Send a test email to verify the configuration:

echo "Test email body" | mail -s "Test email subject" [email protected]

External SMTP Configuration (e.g., Gmail)

Set Up Authentication for External SMTP

Edit the sasl_passwd file to store your SMTP credentials:
```
sudo nano /etc/postfix/sasl_passwd
```
Add your SMTP credentials:
```
[smtp.gmail.com]:587 [email protected]:xyz
```
Important: Replace [email protected] and xyz with your actual Gmail username and app password.
Secure the sasl_passwd File

Set the appropriate permissions and create a hashed database:
```
sudo chmod 600 /etc/postfix/sasl_passwd
sudo postmap /etc/postfix/sasl_passwd
```

Configure Postfix for External SMTP

Edit the Postfix configuration file:

sudo nano /etc/postfix/main.cf

Add or modify the following configurations:

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = jira-server
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = $myhostname, jira-dc10-server, jira-server, localhost.localdomain, localhost
relayhost = [smtp.gmail.com]:587
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all

smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_use_tls = yes
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt

Restart Postfix to Apply Changes
```
sudo systemctl restart postfix
```

Additional Resources

For more detailed external SMTP configuration, refer to resources such as PhoenixNAP's Postfix SMTP Guide (opens in a new tab).

This guide should help you configure Postfix for both local and external SMTP servers. Make sure to replace placeholder values with your actual server details and credentials.

Portrainer Redash