In this guide, we are going to learn how to install and configure Postfix as send-only SMTP server on Fedora 29. Postfix is a free and opensource mail transfer agent (MTA) that routes and delivers emails to the systems that are external to it. In this article, we are going to learn how configure Postfix to act a as send-only SMTP server such that it can only send emails rather than receive nor process them.
Configure Postfix as Send-Only SMTP Server on Fedora 29
Install Postfix on Fedora 29
Postfix is available on Fedora default repos. Before you can install it, ensure that you system packages are up-to-date.
dnf update dnf install postfix
Once the installation is done, proceed to configure Postfix as send-only SMTP server.
Start and enable Postfix to run on system boot
systemctl start postfix
systemctl enable postfix
Configure Postfix as send-only SMTP server
In order for Postfix to process and send mails from the server in which it is running, i.e the
localhost, we need to configure it to listen on the
loopback interface, 127.0.0.1 only. Therefore, open the main configuration file for Postfix,
/etc/postfix/main.cf, for editing and replace the value of
loopback-only if it is not set by default. The
inet_interfaces is set to
localhost by default on Fedora 29. If this is not the case for you, make appropriate adjustments.
... #inet_interfaces = all #inet_interfaces = $myhostname #inet_interfaces = $myhostname, localhost inet_interfaces = localhost # Enable IPv4, and IPv6 if supported inet_protocols = all ...
If you make any changes, be sure to restart Postfix for the changes to take effect.
systemctl restart postfix
Test the Postfix SMTP server
To confirm that your local Postfix can actually send mails, you can try to send a test mail. Replace the
[email protected] with your external email ID.
mail -s "Testing Send-only Postfix SMTP" [email protected] < /dev/null
You should be able to receive an empty mail with subject “Testing Send-only Postfix SMTP” on your email account.
If you encounter an error,
bash: mail: command not found, run the command below to install mail command.
dnf install mailx
Forward System Mails
In order to receive system mails (mails sent to
root user) on an external mail account, you need to configure system mail forwarding. By default, system-generated mails are forwarded to root user on the local system as defined by the following line on
/etc/aliases configuration file.
# Basic system aliases -- these MUST be present. mailer-daemon: postmaster postmaster: root
To forward all mails sent to root user, you need to forward them to your external email address. Therefore, open the aliases configuration file and make the changes as shown below;
# Basic system aliases -- these MUST be present. mailer-daemon: postmaster postmaster: root root: [email protected]
Be sure to replace
[email protected] with your email ID.
In order to rebuild the database for the mail aliases file,
/etc/aliases, run the command
newaliases every time this file is changed in order for the changes to take effect.
Verify Mail Forwarding
Now that the configurations are done, you can test to verify that your send-only SMTP server can send mails. You can use the mail command to do the test as shown below;
echo "Testing Mail Forwarding to Postfix SMTP" | mail -s "Forward System Mails" root
Similarly, you should be able to receive the mail on your external email account.
That is all. You have installed and configure Postfix as Send-Only SMTP Server on Fedora 29. Thank you for reading.
You can also check our previous article on How to Install and Setup iRedMail Mail Server on Ubuntu 18.04 LTS.