Installing a LetsEncrypt SSL Certificate: Difference between revisions

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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}}|}}
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{{KB|{{ZC}}|{{ZCS 10.0}}|{{ZCS 9.0}}|{{ZCS 8.8}}|}}
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[[File:Letsencrypt-en.png|1024px]]
= How to use Zimbra with Let's Encrypt certificates =


==Purpose==
This article is a step-by-step instruction on setting up a Zimbra with Let’s Encrypt certificates.
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==
If you are running a multi server installation of Zimbra it is recommended you set-up a dedicated VM for obtaining the Let’s Encrypt certificate and follow the steps under <code>Manual installation of Let’s Encrypt on Zimbra</code>.
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===
= Prerequisites =
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]]
This guide assumes you are using Ubuntu 20 and you have set up a correct hostname and DNS, to check run the following as user <code>zimbra</code> and verify <code>zmhostname</code> is the same as <code>hostname --fqdn</code>:


*** The process will ask if we agree with the ToS.
<pre>zimbra@le-test:~$ source ~/bin/zmshutil; zmsetvars
zimbra@le-test:~$ zmhostname
le-test.zimbra.tech
zimbra@le-test:~$ hostname --fqdn
le-test.zimbra.tech</pre>
Next you should have set up a CAA DNS record so that Let’s Encrypt can issue certificates for your domain, to check run the following and make sure <code>0 issue &quot;letsencrypt.org&quot;</code> is in the output of the command:


[[File:Letsencrypt-003.png]]
<pre>zimbra@le-test:~$ sudo apt install -y net-tools dnsutils
zimbra@le-test:~$ dig +short type257 $(hostname --d)
0 issuewild &quot;letsencrypt.org&quot;
0 issue &quot;letsencrypt.org&quot;</pre>
Next check if Zimbra listens on port 80, Let’s Encrypt needs to be able to run a temporary webserver on port 80, so it can not be used by Zimbra. This is not an issue as most browsers now try https first. The following command should not have any output:


**** In case we run a renewal, or a request for a new FQDN, the process will just take a few seconds.
<pre>netstat -tulpn | grep &quot;:80 &quot;</pre>
Updating letsencrypt and virtual environment dependencies.......
In case your Zimbra is listening on port 80, you have to switch the proxy mode like this:
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]]
<pre>sudo su zimbra -
zmprov ms `zmhostname` zimbraReverseProxyMailMode https
zmprov ms `zmhostname` zimbraMailMode https
/opt/zimbra/bin/zmtlsctl https
/opt/zimbra/libexec/zmproxyconfig -e -w -o -a 8080:80:8443:443 -x https -H `zmhostname`</pre>
If you are having trouble setting up Zimbra you can use our automated installer that will take care of Let’s Encrypt also: https://github.com/Zimbra/zinstaller


* The process will take a few seconds to validate and then will end:
Further reading:
<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
* https://wiki.zimbra.com/wiki/CLI_zmtlsctl_to_set_Web_Server_Mode
  Donating to EFF:                    https://eff.org/donate-le</pre>
* https://wiki.zimbra.com/wiki/Enabling_Zimbra_Proxy_and_memcached


===Where are the SSL Certificate Files?===
= Installing Certbot =
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
Certbot in the Ubuntu repositories is too old and cannot be used for Zimbra. The newer version can be installed via snap or pip. Run below commands to install Cerbot and obtain a certificate:


'''chain.pem''' is the chain
<pre>apt install -y python3 python3-venv libaugeas0
python3 -m venv /opt/certbot/
/opt/certbot/bin/pip install --upgrade pip
/opt/certbot/bin/pip install certbot
ln -s /opt/certbot/bin/certbot /usr/local/sbin/certbot
/usr/local/sbin/certbot certonly -d $(hostname --fqdn) --standalone --preferred-chain &quot;ISRG Root X1&quot; --agree-tos --register-unsafely-without-email</pre>
Support for ECDSA TLS (elliptic curve cryptography ECC) certificates has been added to Zimbra <code>zmcertmgr</code> from Zimbra versions 10.0.6, Joule-8.8.15-Patch-45, Kepler-9.0.0-Patch-38. Let’s Encrypt Certbot defaults to ECDSA secp256r1 (P-256) since version 2.0.0. If you are running out-of-date versions of the software or have another reason why you are required to use RSA certificates append to to cerbot command the <code>--key-type rsa</code> switch after <code>--register-unsafely-without-email</code>.


'''fullchain.pem''' is the concatenation of cert.pem + chain.pem
= Zimbra deployment =


'''privkey.pem''' is the private key
Create the following script that deploys the Let’s Encrypt certificate on Zimbra:


Please keep in mind that the private key is only for you.
<pre>cat &gt;&gt; /usr/local/sbin/letsencrypt-zimbra &lt;&lt; EOF
#!/bin/bash
/usr/local/sbin/certbot certonly -d $(hostname --fqdn) --standalone -n --preferred-chain  &quot;ISRG Root X1&quot; --agree-tos --register-unsafely-without-email
cp &quot;/etc/letsencrypt/live/$(hostname --fqdn)/privkey.pem&quot; /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
rm -f &quot;/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem&quot;
cp &quot;/etc/letsencrypt/live/$(hostname --fqdn)/chain.pem&quot; &quot;/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem&quot;
cat /tmp/ISRG-X1.pem &gt;&gt; &quot;/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem&quot;
chown zimbra:zimbra /etc/letsencrypt -R
cd /tmp
su zimbra -c '/opt/zimbra/bin/zmcertmgr deploycrt comm &quot;/etc/letsencrypt/live/$(hostname --fqdn)/cert.pem&quot; &quot;/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem&quot;'
rm -f &quot;/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem&quot;
EOF</pre>
Set the correct permission, set up a cron job and run the deployment:


===Build the proper Intermediate CA plus Root CA===
<pre>chmod +rx /usr/local/sbin/letsencrypt-zimbra
Let's Encrypt is almost perfect, but during the files the process built, they just add the chain.pem file without the root CA.
ln -s /usr/local/sbin/letsencrypt-zimbra /etc/cron.daily/letsencrypt-zimbra
You must to use the IdenTrust root Certificate and merge it after the chain.pem
/etc/cron.daily/letsencrypt-zimbra</pre>
* [https://www.identrust.com/certificates/trustid/root-download-x3.html https://www.identrust.com/certificates/trustid/root-download-x3.html]
Finally restart Zimbra to load the new certificate:
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. ===
<pre>sudo su zimbra -c '/opt/zimbra/bin/zmcontrol restart'</pre>
Copy all the Let's Encrypt folder with all files '''/etc/letsencrypt/live/$domain''' into /opt/zimbra/ssl/letsencrypt:
'''''The cron job will renew your certificate about 1 month prior to the expiration date, you need to manually restart Zimbra before the renewal date to load the new certificate.'''''
root@mail2:~# mkdir /opt/zimbra/ssl/letsencrypt
root@mail2:~# cp /etc/letsencrypt/live/mail2.next.zimbra.io/* /opt/zimbra/ssl/letsencrypt/
root@mail2:~# chown zimbra:zimbra /opt/zimbra/ssl/letsencrypt/*
root@mail2:~# ls -la /opt/zimbra/ssl/letsencrypt/
total 24
drwxr-xr-x 2 root  root  4096 Jul 15 22:59 .
drwxr-xr-x 8 zimbra zimbra 4096 Jul 15 22:59 ..
-rw-r--r-- 1 zimbra zimbra 1809 Jul 15 22:59 cert.pem
-rw-r--r-- 1 zimbra zimbra 2847 Jul 15 22:59 chain.pem
-rw-r--r-- 1 zimbra zimbra 3456 Jul 15 22:59 fullchain.pem
-rw-r--r-- 1 zimbra zimbra 1704 Jul 15 22:59 privkey.pem
====Zimbra Collaboration 8.7 and above====
As '''zimbra''' user
<pre>root@zimbra86:/opt/zimbra/ssl/letsencrypt/# /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>


====Zimbra Collaboration 8.6 and previous====
= Manual installation of Let’s Encrypt on Zimbra =
As '''root''' user
<pre>root@zimbra86:/opt/zimbra/ssl/letsencrypt/# /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===
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.
====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 /opt/zimbra/ssl/letsencrypt/privkey.pem /opt/zimbra/ssl/zimbra/commercial/commercial.key


====Final SSL deployment====
After you have received the certificate from Let’s Encrypt you can deploy it on Zimbra like this:
Then deploy the certificate as follows:  
 
=====Zimbra Collaboration 8.7 and above=====
As user root or sudo:
As '''zimbra''' user
 
<pre>zimbra@mail2://opt/zimbra/ssl/letsencrypt/$ /opt/zimbra/bin/zmcertmgr deploycrt comm cert.pem chain.pem  
<pre>cp /etc/letsencrypt/live/barrydegraaff.nl/privkey.pem /opt/zimbra/ssl/zimbra/commercial/commercial.key
** Verifying 'cert.pem' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
chown zimbra:zimbra /opt/zimbra/ssl/zimbra/commercial/commercial.key
Certificate 'cert.pem' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
wget -O /tmp/ISRG-X1.pem https://letsencrypt.org/certs/isrgrootx1.pem.txt
** Verifying 'cert.pem' against 'chain.pem'
cat /tmp/ISRG-X1.pem &gt;&gt; /etc/letsencrypt/live/barrydegraaff.nl/chain.pem</pre>
Valid certificate chain: cert.pem: OK
As user zimbra or <code>sudo su zimbra -</code>:
** Copying 'cert.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
 
** Copying 'chain.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
<pre>cd ~
** Appending ca chain 'chain.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
/opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key /etc/letsencrypt/live/barrydegraaff.nl/cert.pem /etc/letsencrypt/live/barrydegraaff.nl/chain.pem
** 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'
/opt/zimbra/bin/zmcertmgr deploycrt comm /etc/letsencrypt/live/barrydegraaff.nl/cert.pem /etc/letsencrypt/live/barrydegraaff.nl/chain.pem</pre>
The output should be similar to:
 
<pre>root@zimbra9:~# su zimbra -
zimbra@zimbra9:/root$ /opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key /etc/letsencrypt/live/barrydegraaff.nl/cert.pem /etc/letsencrypt/live/barrydegraaff.nl/chain.pem
** Verifying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
Certificate '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
** Verifying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' against '/etc/letsencrypt/live/barrydegraaff.nl/chain.pem'
Valid certificate chain: /etc/letsencrypt/live/barrydegraaff.nl/cert.pem: OK
zimbra@zimbra9:/root$ cd ~
zimbra@zimbra9:~$ /opt/zimbra/bin/zmcertmgr deploycrt comm /etc/letsencrypt/live/barrydegraaff.nl/cert.pem /etc/letsencrypt/live/barrydegraaff.nl/chain.pem
** Verifying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
Certificate '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
** Verifying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' against '/etc/letsencrypt/live/barrydegraaff.nl/chain.pem'
Valid certificate chain: /etc/letsencrypt/live/barrydegraaff.nl/cert.pem: OK
** Copying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
** Copying '/etc/letsencrypt/live/barrydegraaff.nl/chain.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
** Appending ca chain '/etc/letsencrypt/live/barrydegraaff.nl/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.
** NOTE: restart mailboxd to use the imported certificate.
** Saving config key 'zimbraSSLCertificate' via zmprov modifyServer mail2.next.zimbra.io...failed (rc=1)
** Saving config key 'zimbraSSLCertificate' via zmprov modifyServer zimbra9.barrydegraaff.nl...ok
** Saving config key 'zimbraSSLPrivateKey' via zmprov modifyServer zimbra9.barrydegraaff.nl...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'
** 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.crt' to '/opt/zimbra/conf/slapd.crt'
Line 176: Line 141:
** NOTE: restart services to use the new certificates.
** NOTE: restart services to use the new certificates.
** Cleaning up 3 files from '/opt/zimbra/conf/ca'
** Cleaning up 3 files from '/opt/zimbra/conf/ca'
** Removing /opt/zimbra/conf/ca/41b01cbb.0
** Removing /opt/zimbra/conf/ca/ca.key
** Removing /opt/zimbra/conf/ca/ca.key
** Removing /opt/zimbra/conf/ca/e50a23da.0
** Removing /opt/zimbra/conf/ca/ca.pem
** Removing /opt/zimbra/conf/ca/ca.pem
** Copying CA to /opt/zimbra/conf/ca
** 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.key' to '/opt/zimbra/conf/ca/ca.key'
** Copying '/opt/zimbra/ssl/zimbra/ca/ca.pem' to '/opt/zimbra/conf/ca/ca.pem'
** Copying '/opt/zimbra/ssl/zimbra/ca/ca.pem' to '/opt/zimbra/conf/ca/ca.pem'
** Creating CA hash symlink '41b01cbb.0' -> 'ca.pem'
** Creating CA hash symlink 'e50a23da.0' -&gt; 'ca.pem'
** Creating /opt/zimbra/conf/ca/commercial_ca_1.crt
** Creating /opt/zimbra/conf/ca/commercial_ca_1.crt
** Creating CA hash symlink '4f06f81d.0' -> '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 /opt/zimbra/conf/ca/commercial_ca_2.crt
** Creating CA hash symlink '2e5ac55d.0' -> 'commercial_ca_2.crt'</pre>  
** Creating CA hash symlink '4042bcee.0' -&gt; 'commercial_ca_2.crt'</pre>
=====Zimbra Collaboration 8.6 and previous=====
Finally restart Zimbra as user zimbra or <code>sudo su zimbra -</code>:
As '''root''' user
<pre>root@zimbra86:/opt/zimbra/ssl/letsencrypt/# /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:
zmcontrol restart
 
===Test the new SSL Certificate===
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]]
 
You can expand the Certificate Information to see the new SSL Certificate your server is using:


[[File:Letsencrypt-007.png]]
<pre>zmcontrol restart</pre>
= Using DANE =


===Test the new SSL Certificate with OpenSSL===
You have to use Certbot with the <code>--reuse-key</code> option, see https://blog.zimbra.com/2022/04/zimbra-skillz-enable-dane-verification-for-incoming-email-in-zimbra/
You can use openssl cli tools to check and test the new SSL certificate:
echo QUIT | openssl s_client -connect $domain:443 | openssl x509 -noout -text | less
where $domain is the fqdn you used during the process


===Building Multi-SAN SSL Certificate and complex scenarios===
= Using multiple https domains with SNI =
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].


Here is an example using two FQDN:
Refer to: https://blog.zimbra.com/2022/06/zimbra-skillz-how-to-use-zimbra-with-multiple-https-domains-server-name-indication-sni/
./letsencrypt-auto certonly --standalone -d fqdn1 -d fqdn2


===Verifying SSL certificate is not expired===
= Further reading =
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:
* https://techcrunch.com/2021/09/21/lets-encrypt-root-expiry
define command{
        command_name    check_https_vhost
        command_line    /usr/lib/nagios/plugins/check_http --sni -H '$ARG1$' -C 30,14
}


define service{
        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 10.0, 9.0, 8.8|22/09/2022}}
{{NeedSME|Jorge|SME2|Copyeditor}}


[[Category:Certificates]]
[[Category:Certificates]]

Latest revision as of 11:11, 20 December 2023

  1. Zimbra Tech Center
  2. Community Sandbox
  3. Installing a LetsEncrypt SSL Certificate

Installing a Let's Encrypt SSL Certificate

   KB 22434        Last updated on 2023-12-20  




5.00
(one vote)

How to use Zimbra with Let's Encrypt certificates

This article is a step-by-step instruction on setting up a Zimbra with Let’s Encrypt certificates.

If you are running a multi server installation of Zimbra it is recommended you set-up a dedicated VM for obtaining the Let’s Encrypt certificate and follow the steps under Manual installation of Let’s Encrypt on Zimbra.

Prerequisites

This guide assumes you are using Ubuntu 20 and you have set up a correct hostname and DNS, to check run the following as user zimbra and verify zmhostname is the same as hostname --fqdn: 

zimbra@le-test:~$ source ~/bin/zmshutil; zmsetvars
zimbra@le-test:~$ zmhostname
le-test.zimbra.tech
zimbra@le-test:~$ hostname --fqdn
le-test.zimbra.tech

Next you should have set up a CAA DNS record so that Let’s Encrypt can issue certificates for your domain, to check run the following and make sure 0 issue "letsencrypt.org" is in the output of the command: 

zimbra@le-test:~$ sudo apt install -y net-tools dnsutils
zimbra@le-test:~$ dig +short type257 $(hostname --d)
0 issuewild "letsencrypt.org"
0 issue "letsencrypt.org"

Next check if Zimbra listens on port 80, Let’s Encrypt needs to be able to run a temporary webserver on port 80, so it can not be used by Zimbra. This is not an issue as most browsers now try https first. The following command should not have any output: 

netstat -tulpn | grep ":80 "

In case your Zimbra is listening on port 80, you have to switch the proxy mode like this: 

sudo su zimbra -
zmprov ms `zmhostname` zimbraReverseProxyMailMode https
zmprov ms `zmhostname` zimbraMailMode https
/opt/zimbra/bin/zmtlsctl https
/opt/zimbra/libexec/zmproxyconfig -e -w -o -a 8080:80:8443:443 -x https -H `zmhostname`

If you are having trouble setting up Zimbra you can use our automated installer that will take care of Let’s Encrypt also: https://github.com/Zimbra/zinstaller

Further reading:

Installing Certbot

Certbot in the Ubuntu repositories is too old and cannot be used for Zimbra. The newer version can be installed via snap or pip. Run below commands to install Cerbot and obtain a certificate: 

apt install -y python3 python3-venv libaugeas0
python3 -m venv /opt/certbot/
/opt/certbot/bin/pip install --upgrade pip
/opt/certbot/bin/pip install certbot
ln -s /opt/certbot/bin/certbot /usr/local/sbin/certbot
/usr/local/sbin/certbot certonly -d $(hostname --fqdn) --standalone --preferred-chain  "ISRG Root X1" --agree-tos --register-unsafely-without-email

Support for ECDSA TLS (elliptic curve cryptography ECC) certificates has been added to Zimbra zmcertmgr from Zimbra versions 10.0.6, Joule-8.8.15-Patch-45, Kepler-9.0.0-Patch-38. Let’s Encrypt Certbot defaults to ECDSA secp256r1 (P-256) since version 2.0.0. If you are running out-of-date versions of the software or have another reason why you are required to use RSA certificates append to to cerbot command the --key-type rsa switch after --register-unsafely-without-email.

Zimbra deployment

Create the following script that deploys the Let’s Encrypt certificate on Zimbra: 

cat >> /usr/local/sbin/letsencrypt-zimbra << EOF
#!/bin/bash
/usr/local/sbin/certbot certonly -d $(hostname --fqdn) --standalone -n --preferred-chain  "ISRG Root X1" --agree-tos --register-unsafely-without-email
cp "/etc/letsencrypt/live/$(hostname --fqdn)/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
rm -f "/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem"
cp "/etc/letsencrypt/live/$(hostname --fqdn)/chain.pem" "/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem"
cat /tmp/ISRG-X1.pem >> "/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem"
chown zimbra:zimbra /etc/letsencrypt -R
cd /tmp
su zimbra -c '/opt/zimbra/bin/zmcertmgr deploycrt comm "/etc/letsencrypt/live/$(hostname --fqdn)/cert.pem" "/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem"'
rm -f "/etc/letsencrypt/live/$(hostname --fqdn)/chainZimbra.pem"
EOF

Set the correct permission, set up a cron job and run the deployment: 

chmod +rx /usr/local/sbin/letsencrypt-zimbra
ln -s /usr/local/sbin/letsencrypt-zimbra /etc/cron.daily/letsencrypt-zimbra
/etc/cron.daily/letsencrypt-zimbra

Finally restart Zimbra to load the new certificate: 

sudo su zimbra -c '/opt/zimbra/bin/zmcontrol restart'

The cron job will renew your certificate about 1 month prior to the expiration date, you need to manually restart Zimbra before the renewal date to load the new certificate.

Manual installation of Let’s Encrypt 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.nl/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.nl/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.nl/cert.pem /etc/letsencrypt/live/barrydegraaff.nl/chain.pem
/opt/zimbra/bin/zmcertmgr deploycrt comm /etc/letsencrypt/live/barrydegraaff.nl/cert.pem /etc/letsencrypt/live/barrydegraaff.nl/chain.pem

The output should be similar to: 

root@zimbra9:~# su zimbra -
zimbra@zimbra9:/root$ /opt/zimbra/bin/zmcertmgr verifycrt comm /opt/zimbra/ssl/zimbra/commercial/commercial.key /etc/letsencrypt/live/barrydegraaff.nl/cert.pem /etc/letsencrypt/live/barrydegraaff.nl/chain.pem
** Verifying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
Certificate '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
** Verifying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' against '/etc/letsencrypt/live/barrydegraaff.nl/chain.pem'
Valid certificate chain: /etc/letsencrypt/live/barrydegraaff.nl/cert.pem: OK
zimbra@zimbra9:/root$ cd ~
zimbra@zimbra9:~$ /opt/zimbra/bin/zmcertmgr deploycrt comm /etc/letsencrypt/live/barrydegraaff.nl/cert.pem /etc/letsencrypt/live/barrydegraaff.nl/chain.pem
** Verifying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' against '/opt/zimbra/ssl/zimbra/commercial/commercial.key'
Certificate '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' and private key '/opt/zimbra/ssl/zimbra/commercial/commercial.key' match.
** Verifying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' against '/etc/letsencrypt/live/barrydegraaff.nl/chain.pem'
Valid certificate chain: /etc/letsencrypt/live/barrydegraaff.nl/cert.pem: OK
** Copying '/etc/letsencrypt/live/barrydegraaff.nl/cert.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial.crt'
** Copying '/etc/letsencrypt/live/barrydegraaff.nl/chain.pem' to '/opt/zimbra/ssl/zimbra/commercial/commercial_ca.crt'
** Appending ca chain '/etc/letsencrypt/live/barrydegraaff.nl/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 zimbra9.barrydegraaff.nl...ok
** Saving config key 'zimbraSSLPrivateKey' via zmprov modifyServer zimbra9.barrydegraaff.nl...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

Using DANE

You have to use Certbot with the --reuse-key option, see https://blog.zimbra.com/2022/04/zimbra-skillz-enable-dane-verification-for-incoming-email-in-zimbra/

Using multiple https domains with SNI

Refer to: https://blog.zimbra.com/2022/06/zimbra-skillz-how-to-use-zimbra-with-multiple-https-domains-server-name-indication-sni/

Further reading


Verified Against: Zimbra Collaboration 10.0, 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: 2023-12-20



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