Finding a way so that your Postfix will encrypt email? We can help you with it.

Postfix encrypts the email to ensure security over the sending data.

Whereas a nonencrypted email shows a red padlock with a warning message at the receiver end.

So, at Bobcares we often get requests to encrypt emails as a part of our Server Management Services.

Today, let’s see how our Support Engineers encrypt emails and fix TLS errors for our customers.

Why should Postfix encrypt email?

Today, emails are an official communication medium. Many confidential and important data are transmitted via email.

So, encrypting the data sent via email is very important. This can be done by enabling encryption in the mail server.

Postfix is one of a popular Mail Transfer Agent(MTA) for routing and delivering emails.

The best way to encrypt the Postfix mail server is to enable TLS(Transport Layer Security) certificate.

Today, let’s see how to enable TLS for Postfix to encrypt emails.

How we encrypt emails in Postfix?

To secure a Postfix SMTP server with a certificate, the cheapest way is to use Let’s encrypt. This gives a free and valid TLS certificate for your domain name.

The customers can also use a paid certificate for their domain. And this is totally up to the customer.

Above all, the mail server should have a valid TLS certificate.

After having a valid certificate, a few changes in the Postfix configuration file secure the outgoing emails.

For instance, /etc/postfix/main.cf is the configuration file for Postfix in Linux.

So, to encrypt the emails, our Support Team adds a few codes to this file. The most important section of this code is.

smtpd_use_tls=yes
smtp_tls_security_level = encrypt
smtpd_tls_cert_file=<path to cert file>
smtpd_tls_key_file=<path to private key>
smtpd_tls_loglevel = 1

Here the path of cert file and private key depends on the location of the same in the servers. Our Support team ensures to add error-free code. Later, we recheck the configuration file to avoid further errors.

By default, Postfix has a few features to debug errors. The most useful commands are postfix check and postconf.

1. Using Postfix check command

Sometimes, bad directory/file ownership or permissions can cause errors. In such cases, our Support Engineers use the command.

postfix check

This command lists the warnings and creates missing directories. Thus making error fixing easier.

2. Postfix configuration check

Similarly, to debug the configuration file we use the command.

postconf -n

Usually, this command shows the postfix config in action. This is a quite handy and useful feature in Postfix. Because it enables us to check the warning codes in the configuration file.

Errors after Postfix encryption

By using a valid TLS certificate Postfix encrypt email. But improper setup can also show errors while sending mails. Now let’s see a few TLS errors in Postfix.

1. Incorrect permission and ownership of TLS

In many cases, customers approach us with the below error message.

TLS not available due to local problem

This message indicates that TLS is not available. But, the server may have a TLS certificate. Then it indicates that Postfix cannot find the certificate.

Firstly, our Support Team checks the certificate folder path. We make sure that, this is the certificate path in the configuration file.

Secondly, we check the permissions certificate folder and files.

For instance, the files and directory containing the certificate need root permission. We use the chown command to do the same.

Ideally, the recommended permission for folders is 700 and files are 600.

Finally, we restart the Postfix service.

After fixing the error, emails are sent without fail.

2. Protocol settings

Sometimes the configuration setup may use broken and insecure protocol. For instance, the customers approach us with an error message.

TLS library problem

Firstly, our Support Team checks the configuration using the command,

postconf -n

Usually, this gives warning codes. So, if some insecure protocols are found, we remove the same.

In most situations, setting a secure TLS protocol fix the error.

[Still having difficulty to make Postfix encrypt email? – We will do it for you.]

Conclusion

In short, Postfix encrypts email, if the server has a valid TLS certificate. This is very important to ensure security over the data sends via email. We saw how our Support Engineers set it for our customers. We also saw a possible error due to the improper TLS setup.