How to Install a SSL Certificate on Courier IMAP Server?

The Internet Message Access Protocol lets customers access their email accounts using the accessible Courier IMAP server, an MTA (IMAP). It offers a very flexible & scalable mail server that works with different operating systems as Windows, macOS, and Linux.

Hence, if your website is on an IMAP server, you must install the SSL Certificate to protect it.

Generate CSR (Certificate Signing Request)

If you want a simple and stress-free way of generating CSR, you can always consider our CSR generator tool. Add the necessary details and click the “Generate Now” button.

Let’s Start with SSL Installation

Before moving on to the installation process, check your email, where the CA should have sent you the ZIP archive folder containing your primary, root, and intermediate certificates.

Step 1: Create a new PEM file

One of the critical steps is to merge your primary certificate and the private key into a single file.

To begin, download your SSL certificate files and extract them to a directory on your server. Once the files are ready, open your primary certificate and private key files using a text editor like Notepad.

Now, you need to merge the contents of your primary certificate and private key into a new file with the ‘.pem’ extension. You can name the file anything you want, but it should be easy to remember.

To merge the files, copy the encrypted text of your primary SSL certificate and paste it into a new file. Then, copy the encrypted text of your private key and paste it into the same file after the certificate.

Your final PEM file should look like this:

—–BEGIN CERTIFICATE—–
The Encrypted text of your Primary SSL Certificate
—–END CERTIFICATE—–
—–BEGIN RSA PRIVATE KEY—–
The Encrypted text of your Private Key
—–END RSA PRIVATE KEY—–

If an intermediate certificate file is required, you should merge it with your primary certificate and private key. To do this, open your intermediate SSL certificate with any text editor, save it as Intermediate_Cert.txt, and include it in the merged file.

Step 2: Import your SSL Certificate

The next step is to find and open the IMPAD-SSL file, which is available in /usr/lib/courier-imap/etc/ location.

Then add the directives mentioned below to the IMPAD-SSL file:

TLS_CERTFILE=/some/path/mycertificate.pem
TLS_TRUSTCERTS=/some/path/Intermediate_Crt.txt
TLS_PROTOCOL=SSL3

Next, locate and open the POP3D-SSL file. You can also look for it in this path: /usr/lib/courier-imap/etc/. Add the command:

TLS_CERTFILE=/some/path/mycertificate.pem
TLS_TRUSTCERTS=/some/path/Intermediate_Cert.txt

Following this step should import your SSL certificate.

Step 3. Restart your Courier IMAP Server

Once you have made all the relevant changes to both files, all you must do now is restart the Courier IMAP server. It ensures all the SSL certificate changes are applied successfully.

That’s it! You have now successfully installed an SSL certificate on the Courier IMAP server.

However, you must always conduct a scan on your SSL installation via SSL Checker Tool, ensuring no potential errors occur during the installation.