How to Install SSL Cert on Courier IMAP?

If you want to install an SSL certificate on your Courier IMAP server but lack the necessary expertise, this article is for you. We have carefully divided this article into multiple sections to ensure clarity.

CSR Generation

CSR is an encoded text containing crucial details about your domain and organization. You have two distinct options to create a CSR for your IMAP server, each with its unique advantages:

• Use CSR Generation tool – Which automates the CSR and private key creation process.
• Do it manually – More control over the whole process, but it’s tricky and time-consuming.

Steps to Manually Generate a CSR on Courier IMAP Server

Connect to your server, open a prompt, and run the following command:

openssl req -new -nodes -keyout your_domain_name.key -out your_domain_name.csr

Once the CSR is ready, submit it to the CA for validation.

SSL Certificate Installation on Courier IMAP Server

Follow the steps given below to install the SSL cert on the IMAP server:

Step 1: Copy the .zip folder Content

Once the CA verifies your CSR, they will send your SSL certificate and additional files required for the installation process to your registered mail in a .zip folder.

• Unzip the .zip folder.
• Copy all of the certificate files into your local environment.
• Make sure you have:
  • .crt file (main certificate file).ca-bundle file (intermediate certificates)
  • Private Key File

Step 2: Merge Main Certificate File and the Primary Key

• Open the .crt file using a text editor, like Notepad. (Note_1)
• Open the private key file in a different Notepad. (Note _2)
• Open a new Notepad. (Note_3)
• Copy all the content of Note_1 into Note_3.
• Copy all the content of Note_2 into Note_3 without giving any space in between.
• Save the Note 3 with the .pem extension. (Note_3.pem)

Step 3: Import the Certificate

• Open IMPAD-SSL file. (Typically, found at – /usr/lib /courier-imap/etc/)
• Add these commands to the file:

TLS_CERTFILE=/some/path/Note_3.pem
TLS_TRUSTCERTS=/some/path/intermediate.txt

• Verify the underneath cmd that allows the SSL3 version:

TLS_PROTOCOL=SSL3

• Open POP3D-SSL file. (Commonly located at – /usr/lib/courier-imap/etc/)
• Add these two commands in the POP3D-SSL file:

TLS_CERTFILE=/some/path/Note_3.pem
TLS_TRUSTCERTS=/some/path/Intermediace_Cert.txt

Step 4: Restart the Server

Ensure that the file “Note_3.pem” has restricted readability and is accessible exclusively to the root user. Once you have secured the file permissions, proceed to restart the Courier IMAP server.

Congratulations, you have accomplished the installation procedure.

Test the SSL Certificate Installation

To confirm that the SSL certificate on your Courier IMAP Server has been deployed successfully, you can rely on SSL testing tools like SSL Checker.

This dedicated tool is specifically designed to efficiently identify any vulnerabilities or potential errors in your SSL setup. Utilizing SSL Checker, you can acquire an explicit and detailed report that provides comprehensive insights into any issues that may impact and influence your SSL configuration.