Installing SMTP IMAP POP3 SSL Certificate Plesk Linux

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Installing SMTP IMAP POP3 SSL Certificate Plesk Linux

In this tutorial I will be showing you how to Installing Installing SMTP IMAP POP3 SSL Certificate Plesk Linux, works for all Parallels Plesk Panel versions, in this tutorial I’ll be using Parallels Plesk Panel 12 running CloudLinux.

Login as root to the server, or use a sudoer username. Now make  a backup of SMTP, IMAP, POP3 SSL Certificate Files in CentOS, CloudLinux or RedHat based systems to your /root directory.

Type in the below command to find your ssl files.

find / -name imapd.pem

find / -name pop3d.pem


Backup SMTP Postfix SSL Certificate

cp /etc/postfix/postfix_default.pem /root

 Backup Courier Imap SSL Certificate

cp /usr/share/imapd.pem /root


Backup Courier POP3 SSL Certificate

cp /usr/share/pop3d.pem /root 

If using earlier versions of Parallels Plesk Panel your .pem ssl certificates will be in /usr/share/courier-imap/ directory.




Installing SMTP IMAP POP3 SSL Certificate Plesk Linux

Installing SMTP IMAP POP3 SSL Certificate Plesk Linux Email Server Enable SSL Encryption




Creating your SSL Certificate Chain

When creating your ssl certificate chain you need to put them in the correct order, depending on which SSL Certificate you bought. When you buy your SSL Certificate and create the CSR you’ll be emailed with all your ssl certificate files, and you might find instructions on how to bundle them, or download the bundle from their website.

If you bought a Comodo SSL Certificate you can scroll down to see how I installed our Comodo Positive Wildcard SSL Certificate in our email server.

This is the order in which you want to include in your smtp, pop3 and imap ssl certificate files.

1.) Your Private Key

2.) Primary SSL Certificate

3.) Intermediate CA Certificate

4.) Intermediate CA Certificate

5.) Root CA Certificate

Remember to leave no spaces between your SSL Certificate Chain

You might need more Intermediate CA Certificates in your chain depending on which ssl certificate you bought.


How to Install SSL Certificate SMTP, IMAP & POP3 in CentOS, CloudLinux or Redhat Based Systems

Once you have figured out how to install your ssl certificate chain in the correct order, you’ll want to learn how to install ssl certificate smtp, imap & pop3 in CentOS, CloudLinux or Redhat based systems.

Before moving on it’s highly recommended to use Plesk Panel or edit your apache and nginx files manually to add your ssl certificate chain to HTTPS to test to make sure it’s in the correct order. Use these tools below to test your https encryption using http ssl testers.

This is a link to an SSL Certificate Chain Tester, if you want to test your Parallels Plesk Panel SSL use https://Your-Domain:8443

Here is a link to SSL Certificate chain tester running our plesk panel, you’ll see it shows the certificates it used in the correct order. Click it and use your own search to see if your SSL Certificate chain is in the correct order.

Plesk Panel 12 SSL Tester ACSHostings

Another Good SSL Tester is

DigiCert® SSL Installation Diagnostics Tool


Installing Postfix SMTP SSL Certificate

nano /etc/postfix/postfix_default.pem

Paste your ssl certificate chain inside.


Installing Courier POP3 SSL Certificate

nano /usr/share/pop3d.pem

Paste your ssl certificate chain inside.

Installing Courier IMAP SSL Certificate

nano /usr/share/imapd.pem

Paste your ssl certificate chain inside.


Now you need to restart the Postfix, Courier-Imapd, Courier-Imaps, Courier-POP3d and Courier-POP3s services

/etc/init.d/postfix restart
/etc/init.d/courier-imapd restart
/etc/init.d/courier-imaps restart
/etc/init.d/courier-pop3d restart
/etc/init.d/courier-pop3s restart

If all has gone well you will have successfully installed your ssl certificate in postfix, courier imap and courier pop3.


Install Comodo PositiveSSL Wildcard w/ New COMODO RSA Domain Validation Secure Server CA Certificates

In this tutorial I’ll be using a Comodo PositiveSSL Wildcard Certificate. The new Comodo PositiveSSL Wildcard Certificate has a new Intermediate CA Certificate called COMODO RSA Domain Validation Secure Server CA with file name COMODODORSADomainValidationSecureServerCA.crt which I’ll be showing you where to include it in your SSL Certificate Chain.

The Private Key and Certificate you will have those by now from your provider. In the POP3, IMAP and POP3 SSL Certificate files your Private Key will be first and your Certificate will be second, CA Certificate Chain will be at the end.

If you want to create a CA Certificate chain you can put these in a file, but we’ll skip that and create the whole file you’ll be posting inside ssl certificate files.

1.) COMODO RSA Domain Validation Secure Server CA – COMODORSADomainValidationSecureServerCA.crt

2. ) COMODO RSA Certification Authority – COMODORSAAddTrustCA.crt
3.) AddTrust External CA Root – AddTrustExternalCARoot.crt

The SSL Certificate Chain Must Be In The Correct Order:

1.) Private Key

2.) Certificate

3.) CA Certificate Chain

nano /etc/postfix/postfix_default.pem

nano /usr/share/pop3d.pem

nano /usr/share/imapd.pem

Now Restart The Email Services

/etc/init.d/postfix restart
/etc/init.d/courier-imapd restart
/etc/init.d/courier-imaps restart
/etc/init.d/courier-pop3d restart
/etc/init.d/courier-pop3s restart


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