Install a Sectigo Domain Validation SSL certificate in Zimbra

We usually get the below four files from Sectigo in the certificate bundle. The file name may vary depending on the certificate type

1. yourdomain.com.crt – main certificate
2. AAACertificateServices.crt – Root Certificate
3. USERTrustRSAAAACA.crt – Intermediate Certificate – 1
4. SectigoRSADomainValidationSecureServerCA.crt – Intermediate Certificate – 2

Step 1: We shall create two files as below.

commercial_ca.crt (includes root certificate and two intermediate certificates)
commercial.crt (includes main certificate, root certificate and two intermediate certificates)

Step 2: Login to Zimbra server, move to directory /opt/zimbra/ssl/zimbra/commercial and create two files as below.

root@mail:~# cd /opt/zimbra/ssl/zimbra/commercial/
root@mail:/opt/zimbra/ssl/zimbra/commercial# touch commercial_ca.crt
root@mail:/opt/zimbra/ssl/zimbra/commercial# touch commercial.crt

Step 3: Provide ownership to Zimbra.

root@mail:/opt/zimbra/ssl/zimbra/commercial# chown zimbra:zimbra commercial_ca.crt
root@mail:/opt/zimbra/ssl/zimbra/commercial# chown zimbra:zimbra commercial.crt

Step 4: Add the certificates into respective files as mentioned above.

root@mail:/opt/zimbra/ssl/zimbra/commercial# vim commercial_ca.crt

-----BEGIN CERTIFICATE-----
<root certificate is here>
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
<intermediate certificate 1 is here>
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
<intermediate certificate 2 is here>
-----END CERTIFICATE-----

root@mail:/opt/zimbra/ssl/zimbra/commercial# vim commercial.crt

-----BEGIN CERTIFICATE-----
<main certificate is here>
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
<root certificate is here>
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
<intermediate certificate 1 is here>
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
<intermediate certificate 2 is here>
-----END CERTIFICATE-----

Step 5: Execute below command as Zimbra user to verify the certificate.

zimbra@mail:~/ssl/zimbra/commercial$ /opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key /opt/zimbra/ssl/zimbra/commercial/commercial.crt /opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt

The output of this command shall look like below.

** Verifying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'

Certificate '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.

** Verifying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' against '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'

Valid certificate chain: /opt/zimbra/ssl/zimbra/commercial/commercial.crt: OK

We shall not proceed further if we get any error here. We have to resolve the error first and then install the certificate following step 6.

Step 6: Install the certificate.

zimbra@mail:~/ssl/zimbra/commercial$ /opt/zimbra/bin/zmcertmgr deploycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.crt /opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt

The output should look like below.

** Keeping first certificate in '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
** Verifying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
Certificate '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
** Verifying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' against '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
Valid certificate chain: /opt/zimbra/ssl/zimbra/commercial/commercial.crt: OK
** Appending ca chain '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt' to '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
** Importing cert '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt' as 'zcs-user-commercial_ca' into cacerts '/opt/zimbra/common/lib/jvm/java/jre/lib/security/cacerts'
** NOTE: restart mailboxd to use the imported certificate.
** Saving config key 'zimbraSSLCertificate' via zmprov modifyServer mail.outpacebd.com...ok
** Saving config key 'zimbraSSLPrivateKey' via zmprov modifyServer mail.outpacebd.com...ok
** Installing imapd certificate '/opt/zimbra/conf/imapd.crt' and key '/opt/zimbra/conf/imapd.key'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' to '/opt/zimbra/conf/imapd.crt'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.key' to '/opt/zimbra/conf/imapd.key'
** Creating file '/opt/zimbra/ssl/zimbra/jetty.pkcs12'
** Creating keystore '/opt/zimbra/conf/imapd.keystore'
** Installing ldap certificate '/opt/zimbra/conf/slapd.crt' and key '/opt/zimbra/conf/slapd.key'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' to '/opt/zimbra/conf/slapd.crt'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.key' to '/opt/zimbra/conf/slapd.key'
** Creating file '/opt/zimbra/ssl/zimbra/jetty.pkcs12'
** Creating keystore '/opt/zimbra/mailboxd/etc/keystore'
** Installing mta certificate '/opt/zimbra/conf/smtpd.crt' and key '/opt/zimbra/conf/smtpd.key'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' to '/opt/zimbra/conf/smtpd.crt'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.key' to '/opt/zimbra/conf/smtpd.key'
** Installing proxy certificate '/opt/zimbra/conf/nginx.crt' and key '/opt/zimbra/conf/nginx.key'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.crt' to '/opt/zimbra/conf/nginx.crt'
** Copying '/opt/zimbra/ssl/zimbra/commercial/commercial.key' to '/opt/zimbra/conf/nginx.key'
** NOTE: restart services to use the new certificates.
** Copying CA to /opt/zimbra/conf/ca
** Copying '/opt/zimbra/ssl/zimbra/ca/ca.key' to '/opt/zimbra/conf/ca/ca.key'
** Copying '/opt/zimbra/ssl/zimbra/ca/ca.pem' to '/opt/zimbra/conf/ca/ca.pem'
** Creating CA hash symlink 'a23bec5a.0' -> 'ca.pem'
** Creating /opt/zimbra/conf/ca/commercial_ca_1.crt
** Creating CA hash symlink 'ee64a828.0' -> 'commercial_ca_1.crt'
** Creating /opt/zimbra/conf/ca/commercial_ca_2.crt
** Creating CA hash symlink '65ff7287.0' -> 'commercial_ca_2.crt'
** Creating /opt/zimbra/conf/ca/commercial_ca_3.crt
** Creating CA hash symlink 'fc5a8f99.0' -> 'commercial_ca_3.crt'

Step 7: Restart Zimbra service to take effect the changes.

zimbra@mail:~$ zmcontrol restart

Hope this helps .

Src: https://learnandgains.blogspot.com/2020/06/install-comodosectigo-domain-validation.html