Difference between revisions of "Installing a LetsEncrypt SSL Certificate"

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=Installing a Let's Encrypt SSL Certificate=
 
=Installing a Let's Encrypt SSL Certificate=
{{KB|{{Unsupported}}|{{ZCS 8.0}}|{{ZCS 7.0}}|}}
+
{{KB|{{Unsupported}}|{{ZCS 9.0}}|{{ZCS 8.8}}|}}
{{WIP}}
 
 
 
[[File:Letsencrypt-en.png|1024px]]
 
  
 
==Purpose==
 
==Purpose==
Step by Step Wiki/KB article to install a Let's Encrypt Commercial Certificate.
 
'''Disclaimer'''
 
The Let’s Encrypt Client is '''BETA SOFTWARE'''. It contains plenty of bugs and rough edges, and it should be tested thoroughly in staging environments before use on production systems.
 
For more information regarding the status of the project, please see https://letsencrypt.org. Be sure to check out the [https://community.letsencrypt.org/t/frequently-asked-questions-faq/26#topic-title Frequently Asked Questions (FAQ)].
 
 
==Resolution==
 
Let’s Encrypt is a new Certificate Authority: It’s free, automated, and open. It could be an option to protect Zimbra Servers with a valid SSL certificate; however, please be aware that is a Beta for now. Some stuff could not work or have issues, so use it at your own risk.
 
 
===Installing Let's Encrypt on a Zimbra Server===
 
Let's Encrypt must be installed on one Linux machine to obtain the proper SSL Certificate, CA Intermediate, and Private Key. It is not required that it be on the same Zimbra Server, but it could save time and help to obtain the renewals, etc.
 
* First Step is to stop the jetty or nginx service at Zimbra level
 
zmproxyctl stop
 
zmmailboxdctl stop
 
* Second step is to Install git on the Server (apt-get install git/yum install git), and then do a git clone of the project on the folder we want
 
** Note: On RedHat/CentOS 6 you will need to enable the EPEL repository before install.
 
git clone https://github.com/letsencrypt/letsencrypt
 
cd letsencrypt
 
* Let's now run Let's Encrypt in auto mode and use the certonly option, because for now the project can't automatically install the cert on Zimbra servers.
 
root@zimbra86:~/tmp/letsencrypt# ./letsencrypt-auto certonly
 
** (This step only happens the first time. This process will not occur when renewing the SSL Certificate if using the same machine.) The process will download all of the OS dependencies that Let's Encrypt needs, and after a few minutes:
 
<pre>Creating virtual environment...
 
Updating letsencrypt and virtual environment dependencies...../root/.local/share/letsencrypt/local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:90: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
 
  InsecurePlatformWarning
 
./root/.local/share/letsencrypt/local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:90: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
 
  InsecurePlatformWarning
 
</pre>
 
*** The process will ask for an Email Address in case of emergency contact or to recover the lost key.
 
 
[[File:Letsencrypt-002.png]]
 
 
*** The process will ask if we agree with the ToS.
 
 
[[File:Letsencrypt-003.png]]
 
 
**** In case we run a renewal, or a request for a new FQDN, the process will just take a few seconds.
 
Updating letsencrypt and virtual environment dependencies.......
 
Running with virtualenv: /root/.local/share/letsencrypt/bin/letsencrypt certonly
 
*** Let's Encrypt will prompt for the domain to protect, in this lab case (zimbra86.zimbra.io):
 
 
[[File:Letsencrypt-004.png]]
 
 
* The process will take a few seconds to validate and then will end:
 
<pre>IMPORTANT NOTES:
 
- Congratulations! Your certificate and chain have been saved at
 
  /etc/letsencrypt/live/zimbra86.zimbra.io/fullchain.pem. Your cert
 
  will expire on 2016-03-04. To obtain a new version of the
 
  certificate in the future, simply run Let's Encrypt again.
 
- If like Let's Encrypt, please consider supporting our work by:
 
 
  Donating to ISRG / Let's Encrypt:  https://letsencrypt.org/donate
 
  Donating to EFF:                    https://eff.org/donate-le</pre>
 
 
===Where are the SSL Certificate Files?===
 
You can find all your files under '''/etc/letsencrypt/live/$domain''', where $domain is the fqdn you used during the process:
 
<pre>root@zimbra86:/etc/letsencrypt/live/zimbra86.zimbra.io# ls -al
 
total 8
 
drwxr-xr-x 2 root root 4096 Dec  5 16:46 .
 
drwx------ 3 root root 4096 Dec  5 16:46 ..
 
lrwxrwxrwx 1 root root  42 Dec  5 16:46 cert.pem -> ../../archive/zimbra86.zimbra.io/cert1.pem
 
lrwxrwxrwx 1 root root  43 Dec  5 16:46 chain.pem -> ../../archive/zimbra86.zimbra.io/chain1.pem
 
lrwxrwxrwx 1 root root  47 Dec  5 16:46 fullchain.pem -> ../../archive/zimbra86.zimbra.io/fullchain1.pem
 
lrwxrwxrwx 1 root root  45 Dec  5 16:46 privkey.pem -> ../../archive/zimbra86.zimbra.io/privkey1.pem</pre>
 
 
'''cert.pem''' is the certificate
 
 
'''chain.pem''' is the chain
 
 
'''fullchain.pem''' is the concatenation of cert.pem + chain.pem
 
 
'''privkey.pem''' is the private key
 
 
Please keep in mind that the private key is only for you.
 
 
===Build the proper Intermediate CA plus Root CA===
 
Let's Encrypt is almost perfect, but during the files the process built, they just add the chain.pem file without the root CA.
 
You must to use the IdenTrust root Certificate and merge it after the chain.pem
 
* [https://www.identrust.com/certificates/trustid/root-download-x3.html https://www.identrust.com/certificates/trustid/root-download-x3.html]
 
Your chain.pem should look like:
 
<pre>
 
-----BEGIN CERTIFICATE-----
 
YOURCHAIN
 
-----END CERTIFICATE-----
 
-----BEGIN CERTIFICATE-----
 
MIIDSjCCAjKgAwIBAgIQRK+wgNajJ7qJMDmGLvhAazANBgkqhkiG9w0BAQUFADA/
 
MSQwIgYDVQQKExtEaWdpdGFsIFNpZ25hdHVyZSBUcnVzdCBDby4xFzAVBgNVBAMT
 
DkRTVCBSb290IENBIFgzMB4XDTAwMDkzMDIxMTIxOVoXDTIxMDkzMDE0MDExNVow
 
PzEkMCIGA1UEChMbRGlnaXRhbCBTaWduYXR1cmUgVHJ1c3QgQ28uMRcwFQYDVQQD
 
Ew5EU1QgUm9vdCBDQSBYMzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEB
 
AN+v6ZdQCINXtMxiZfaQguzH0yxrMMpb7NnDfcdAwRgUi+DoM3ZJKuM/IUmTrE4O
 
rz5Iy2Xu/NMhD2XSKtkyj4zl93ewEnu1lcCJo6m67XMuegwGMoOifooUMM0RoOEq
 
OLl5CjH9UL2AZd+3UWODyOKIYepLYYHsUmu5ouJLGiifSKOeDNoJjj4XLh7dIN9b
 
xiqKqy69cK3FCxolkHRyxXtqqzTWMIn/5WgTe1QLyNau7Fqckh49ZLOMxt+/yUFw
 
7BZy1SbsOFU5Q9D8/RhcQPGX69Wam40dutolucbY38EVAjqr2m7xPi71XAicPNaD
 
aeQQmxkqtilX4+U9m5/wAl0CAwEAAaNCMEAwDwYDVR0TAQH/BAUwAwEB/zAOBgNV
 
HQ8BAf8EBAMCAQYwHQYDVR0OBBYEFMSnsaR7LHH62+FLkHX/xBVghYkQMA0GCSqG
 
SIb3DQEBBQUAA4IBAQCjGiybFwBcqR7uKGY3Or+Dxz9LwwmglSBd49lZRNI+DT69
 
ikugdB/OEIKcdBodfpga3csTS7MgROSR6cz8faXbauX+5v3gTt23ADq1cEmv8uXr
 
AvHRAosZy5Q6XkjEGB5YGV8eAlrwDPGxrancWYaLbumR9YbK+rlmM6pZW87ipxZz
 
R8srzJmwN0jP41ZL9c8PDHIyh8bwRLtTcm1D9SZImlJnt1ir/md2cXjbDaJWFBM5
 
JDGFoqgCWjBH4d1QB7wCCZAA62RjYJsWvIjJEubSfZGL+T0yjWW06XyxV3bqxbYo
 
Ob8VZRzI9neWagqNdwvYkQsEjgfbKbYK7p2CNTUQ
 
-----END CERTIFICATE-----</pre>
 
To sum up: chain.pem has to be concatened with the root CA. First the chain and the end of the file the root CA. The order is important.
 
  
===Verify your commercial certificate. ===
+
Let’s Encrypt is a way to obtain trusted and free TLS certificates. To obtain certificates you can use a program called Certbot. You can find instructions for setting up certbot at https://certbot.eff.org/instructions. If you already use Let’s Encrypt on Zimbra keep reading as this post will explain how to keep using Let’s Encrypt after the expiration of IdentTrust DST Root CA X3 on September 30!
Move to the Let's Encrypt folder with all files '''/etc/letsencrypt/live/$domain''' and then launch the next command as '''root''':
 
<pre>root@zimbra86:/etc/letsencrypt/live/zimbra86.zimbra.io# /opt/zimbra/bin/zmcertmgr verifycrt comm privkey.pem cert.pem chain.pem
 
** Verifying cert.pem against privkey.pem
 
Certificate (cert.pem) and private key (privkey.pem) match.
 
Valid Certificate: cert.pem: OK</pre>
 
  
===Deploy the new Let's Encrypt SSL certificate===
+
In many cases it is easiest to set-up a dedicated VM to take care of the deployment of Let’s Encrypt certificates to all the systems you intent to use with TLS certificates.
====Backup Zimbra SSL directory====
 
Before deploying a good practice is to make a backup.
 
cp -a /opt/zimbra/ssl/zimbra /opt/zimbra/ssl/zimbra.$(date "+%Y%m%d")
 
====Copy the private key under Zimbra SSL path====
 
Before deploying the SSL Certificate, you need to move the privkey.pem under the Zimbra SSL commercial path, like this:
 
cp /etc/letsencrypt/live/zimbra86.zimbra.io/privkey.pem /opt/zimbra/ssl/zimbra/commercial/commercial.key
 
  
====Final SSL deployment====
+
If you want to use Zimbra it is recommended you use the <code>snap</code> version of Certbot as that supports the <code>--preferred-chain  &quot;ISRG Root X1&quot;</code> option which is needed to make it work with Zimbra.
Then deploy the certificate as follows:
 
<pre>root@zimbra86:/etc/letsencrypt/live/zimbra86.zimbra.io# /opt/zimbra/bin/zmcertmgr deploycrt comm cert.pem chain.pem
 
** Verifying cert.pem against /opt/zimbra/ssl/zimbra/commercial/commercial.key
 
Certificate (cert.pem) and private key (/opt/zimbra/ssl/zimbra/commercial/commercial.key) match.
 
Valid Certificate: cert.pem: OK
 
** Copying cert.pem to /opt/zimbra/ssl/zimbra/commercial/commercial.crt
 
** Appending ca chain chain.pem to /opt/zimbra/ssl/zimbra/commercial/commercial.crt
 
** Importing certificate /opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt to CACERTS as zcs-user-commercial_ca...done.
 
** NOTE: mailboxd must be restarted in order to use the imported certificate.
 
** Saving server config key zimbraSSLCertificate...failed.
 
** Saving server config key zimbraSSLPrivateKey...failed.
 
** Installing mta certificate and key...done.
 
** Installing slapd certificate and key...done.
 
** Installing proxy certificate and key...done.
 
** Creating pkcs12 file /opt/zimbra/ssl/zimbra/jetty.pkcs12...done.
 
** Creating keystore file /opt/zimbra/mailboxd/etc/keystore...done.
 
** Installing CA to /opt/zimbra/conf/ca...done.</pre>
 
  
Then you need to restart the services, which will restart the nginx or jetty you stopped before:
+
= Installing the obtained certificate on Zimbra =
zmcontrol restart
 
  
===Test the new SSL Certificate===
+
Make sure to request a certificate with the <code>--preferred-chain  &quot;ISRG Root X1&quot;</code> option. In case you already have a certificate but you have not used the option, you have to do a force renewal with the <code>--force-renewal --preferred-chain  &quot;ISRG Root X1&quot;</code> options.
The last step is to go to your Web Browser and open the URL of your Zimbra server where you installed the Let's Encrypt SSL Certificate:
 
  
[[File:Letsencrypt-006.png|1024px]]
+
After you have received the certificate from Let’s Encrypt you can deploy it on Zimbra like this:
  
You can expand the Certificate Information to see the new SSL Certificate your server is using:
+
As user root or sudo:
  
[[File:Letsencrypt-007.png]]
+
<pre>cp /etc/letsencrypt/live/barrydegraaff.tk/privkey.pem /opt/zimbra/ssl/zimbra/commercial/commercial.key
 +
chown zimbra:zimbra /opt/zimbra/ssl/zimbra/commercial/commercial.key
 +
wget -O /tmp/ISRG-X1.pem https://letsencrypt.org/certs/isrgrootx1.pem.txt
 +
cat /tmp/ISRG-X1.pem &gt;&gt; /etc/letsencrypt/live/barrydegraaff.tk/chain.pem</pre>
 +
As user zimbra or <code>sudo su zimbra -</code>:
  
===Test the new SSL Certificate with OpenSSL===
+
<pre>cd ~
You can use openssl cli tools to check and test the new SSL certificate:
+
/opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key /etc/letsencrypt/live/barrydegraaff.tk/cert.pem /etc/letsencrypt/live/barrydegraaff.tk/chain.pem
echo QUIT | openssl s_client -connect $domain:443 | openssl x509 -noout -text | less
+
/opt/zimbra/bin/zmcertmgr deploycrt comm /etc/letsencrypt/live/barrydegraaff.tk/cert.pem /etc/letsencrypt/live/barrydegraaff.tk/chain.pem</pre>
where $domain is the fqdn you used during the process
+
The output should be similar to:
  
===Building Multi-SAN SSL Certificate and complex scenarios===
+
<pre>root@zimbra91:~# su zimbra -
You can do almost everything you need, like Subject Alt Names, different domains, etc. But to see more about this, visit [https://letsencrypt.org/ the web of the official project].
+
zimbra@zimbra91:/root$ /opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key /etc/letsencrypt/live/barrydegraaff.tk/cert.pem /etc/letsencrypt/live/barrydegraaff.tk/chain.pem
 +
** Verifying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
 +
Certificate '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
 +
** Verifying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' against '/etc/letsencrypt/live/barrydegraaff.tk/chain.pem'
 +
Valid certificate chain: /etc/letsencrypt/live/barrydegraaff.tk/cert.pem: OK
 +
zimbra@zimbra91:/root$ cd ~
 +
zimbra@zimbra91:~$ /opt/zimbra/bin/zmcertmgr deploycrt comm /etc/letsencrypt/live/barrydegraaff.tk/cert.pem /etc/letsencrypt/live/barrydegraaff.tk/chain.pem
 +
** Verifying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
 +
Certificate '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
 +
** Verifying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' against '/etc/letsencrypt/live/barrydegraaff.tk/chain.pem'
 +
Valid certificate chain: /etc/letsencrypt/live/barrydegraaff.tk/cert.pem: OK
 +
** Copying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
 +
** Copying '/etc/letsencrypt/live/barrydegraaff.tk/chain.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
 +
** Appending ca chain '/etc/letsencrypt/live/barrydegraaff.tk/chain.pem' 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/lib/security/cacerts'
 +
** NOTE: restart mailboxd to use the imported certificate.
 +
** Saving config key 'zimbraSSLCertificate' via zmprov modifyServer zimbra91.barrydegraaff.tk...ok
 +
** Saving config key 'zimbraSSLPrivateKey' via zmprov modifyServer zimbra91.barrydegraaff.tk...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.
 +
** Cleaning up 3 files from '/opt/zimbra/conf/ca'
 +
** Removing /opt/zimbra/conf/ca/ca.key
 +
** Removing /opt/zimbra/conf/ca/e50a23da.0
 +
** Removing /opt/zimbra/conf/ca/ca.pem
 +
** 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 'e50a23da.0' -&gt; 'ca.pem'
 +
** Creating /opt/zimbra/conf/ca/commercial_ca_1.crt
 +
** Creating CA hash symlink '8d33f237.0' -&gt; 'commercial_ca_1.crt'
 +
** Creating /opt/zimbra/conf/ca/commercial_ca_2.crt
 +
** Creating CA hash symlink '4042bcee.0' -&gt; 'commercial_ca_2.crt'</pre>
 +
Finally restart Zimbra as user zimbra or <code>sudo su zimbra -</code>:
  
Here is an example using two FQDN:
+
<pre>zmcontrol restart</pre>
./letsencrypt-auto certonly --standalone -d fqdn1 -d fqdn2
 
  
===Verifying SSL certificate is not expired===
+
Please note: You have to concatenate the isrgrootx1.pem CA certificate to the chain to make it work!! That’s it for using Let’s Encrypt on Zimbra!
SSL certificates issued by let's encrypt are valid for 90 days during the BETA phase.
 
You need to check the expiration of your SSL certificate. We can suggest using monitoring tools like Nagios. With nagios plugins there's a command which can check the expiration:
 
/usr/lib/nagios/plugins/check_http --sni -H '<FQDN>' -C 30,14
 
A warning will be issued 30 days before the expiration, a critical will be issued 14 days before the expiration.
 
  
Here is a nagios config file excerpt:
+
= Further reading =
define command{
 
        command_name    check_https_vhost
 
        command_line    /usr/lib/nagios/plugins/check_http --sni -H '$ARG1$' -C 30,14
 
}
 
  
define service{
+
* https://techcrunch.com/2021/09/21/lets-encrypt-root-expiry
        use generic-service
 
        host_name <FQDN>
 
        service_description SSL <FQDN>
 
        check_command check_https_vhost!<FQDN>
 
}
 
  
==Additional Content==
 
* Let's Encrypt User Manual - https://letsencrypt.readthedocs.org/en/latest/using.html
 
* Let's Encrypt Official Project - https://letsencrypt.org/
 
  
{{Article Footer|Zimbra Collaboration 8.6, 8.5|12/05/2015}}
+
{{Article Footer|Zimbra Collaboration 9.0, 8.8|22/09/2022}}
 
{{NeedSME|Jorge|SME2|Copyeditor}}
 
{{NeedSME|Jorge|SME2|Copyeditor}}
  
 
[[Category:Certificates]]
 
[[Category:Certificates]]

Latest revision as of 08:31, 23 September 2021

Installing a Let's Encrypt SSL Certificate

   KB 22434        Last updated on 2021-09-23  




5.00
(one vote)

Purpose

Let’s Encrypt is a way to obtain trusted and free TLS certificates. To obtain certificates you can use a program called Certbot. You can find instructions for setting up certbot at https://certbot.eff.org/instructions. If you already use Let’s Encrypt on Zimbra keep reading as this post will explain how to keep using Let’s Encrypt after the expiration of IdentTrust DST Root CA X3 on September 30!

In many cases it is easiest to set-up a dedicated VM to take care of the deployment of Let’s Encrypt certificates to all the systems you intent to use with TLS certificates.

If you want to use Zimbra it is recommended you use the snap version of Certbot as that supports the --preferred-chain "ISRG Root X1" option which is needed to make it work with Zimbra.

Installing the obtained certificate on Zimbra

Make sure to request a certificate with the --preferred-chain "ISRG Root X1" option. In case you already have a certificate but you have not used the option, you have to do a force renewal with the --force-renewal --preferred-chain "ISRG Root X1" options.

After you have received the certificate from Let’s Encrypt you can deploy it on Zimbra like this:

As user root or sudo:

cp /etc/letsencrypt/live/barrydegraaff.tk/privkey.pem /opt/zimbra/ssl/zimbra/commercial/commercial.key
chown zimbra:zimbra /opt/zimbra/ssl/zimbra/commercial/commercial.key
wget -O /tmp/ISRG-X1.pem https://letsencrypt.org/certs/isrgrootx1.pem.txt
cat /tmp/ISRG-X1.pem >> /etc/letsencrypt/live/barrydegraaff.tk/chain.pem

As user zimbra or sudo su zimbra -:

cd ~
/opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key /etc/letsencrypt/live/barrydegraaff.tk/cert.pem /etc/letsencrypt/live/barrydegraaff.tk/chain.pem
/opt/zimbra/bin/zmcertmgr deploycrt comm /etc/letsencrypt/live/barrydegraaff.tk/cert.pem /etc/letsencrypt/live/barrydegraaff.tk/chain.pem

The output should be similar to:

root@zimbra91:~# su zimbra -
zimbra@zimbra91:/root$ /opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key /etc/letsencrypt/live/barrydegraaff.tk/cert.pem /etc/letsencrypt/live/barrydegraaff.tk/chain.pem
** Verifying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
Certificate '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
** Verifying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' against '/etc/letsencrypt/live/barrydegraaff.tk/chain.pem'
Valid certificate chain: /etc/letsencrypt/live/barrydegraaff.tk/cert.pem: OK
zimbra@zimbra91:/root$ cd ~
zimbra@zimbra91:~$ /opt/zimbra/bin/zmcertmgr deploycrt comm /etc/letsencrypt/live/barrydegraaff.tk/cert.pem /etc/letsencrypt/live/barrydegraaff.tk/chain.pem
** Verifying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
Certificate '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
** Verifying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' against '/etc/letsencrypt/live/barrydegraaff.tk/chain.pem'
Valid certificate chain: /etc/letsencrypt/live/barrydegraaff.tk/cert.pem: OK
** Copying '/etc/letsencrypt/live/barrydegraaff.tk/cert.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
** Copying '/etc/letsencrypt/live/barrydegraaff.tk/chain.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
** Appending ca chain '/etc/letsencrypt/live/barrydegraaff.tk/chain.pem' 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/lib/security/cacerts'
** NOTE: restart mailboxd to use the imported certificate.
** Saving config key 'zimbraSSLCertificate' via zmprov modifyServer zimbra91.barrydegraaff.tk...ok
** Saving config key 'zimbraSSLPrivateKey' via zmprov modifyServer zimbra91.barrydegraaff.tk...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.
** Cleaning up 3 files from '/opt/zimbra/conf/ca'
** Removing /opt/zimbra/conf/ca/ca.key
** Removing /opt/zimbra/conf/ca/e50a23da.0
** Removing /opt/zimbra/conf/ca/ca.pem
** 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 'e50a23da.0' -> 'ca.pem'
** Creating /opt/zimbra/conf/ca/commercial_ca_1.crt
** Creating CA hash symlink '8d33f237.0' -> 'commercial_ca_1.crt'
** Creating /opt/zimbra/conf/ca/commercial_ca_2.crt
** Creating CA hash symlink '4042bcee.0' -> 'commercial_ca_2.crt'

Finally restart Zimbra as user zimbra or sudo su zimbra -:

zmcontrol restart

Please note: You have to concatenate the isrgrootx1.pem CA certificate to the chain to make it work!! That’s it for using Let’s Encrypt on Zimbra!

Further reading


Verified Against: Zimbra Collaboration 9.0, 8.8 Date Created: 22/09/2022
Article ID: https://wiki.zimbra.com/index.php?title=Installing_a_LetsEncrypt_SSL_Certificate Date Modified: 2021-09-23



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Wiki/KB reviewed by Jorge SME2 Copyeditor Last edit by Barry de Graaff
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