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=Multiple SSL Certificates, Server Name Indication (SNI) for HTTPS=
{{KB|{{ZC}}|{{ZCS 8.8}}|{{ZCS 8.7}}||}}
<div class="alert alert-dark fade in"> <p><strong>Note: This feature will not enable SSL Certificate for IMAP/POP or smtps connections. [https://bugzilla.zimbra.com/show_bug.cgi?id=103362 RFE #103362]</strong> </p></div> 

[https://en.wikipedia.org/wiki/Server_Name_Indication '''Server Name Indication (SNI)'''] is an extension to the TLS computer networking protocol by which a client indicates which hostname it is attempting to connect to at the start of the handshaking process. This allows a server to present multiple certificates on the same IP address and TCP port number and hence allows multiple secure (HTTPS) websites (or any other Service over TLS) to be served off the same IP address without requiring all those sites to use the same certificate. It is the conceptual equivalent to HTTP/1.1 name-based virtual hosting, but for HTTPS. The desired hostname is not encrypted, so an eavesdropper can see which site is being requested.

To make SNI useful, as with any protocol, the vast majority of visitors must use web browsers that implement it. Users whose browsers do not implement SNI are presented with a default certificate and hence are likely to receive certificate warnings. [https://en.wikipedia.org/wiki/Server_Name_Indication Source:Wikipedia]

==Getting Started==
Zimbra Collaboration supports SSL SNI starting at the 8.7 Release.  The support requires and uses features of the Proxy service (which is actually required by Zimbra Collaboration 8.7 anyway)
[[File:Zimbra-ssl-sni-001.png]]

==Prerequisites==
* Zimbra proxy service must be installed and enabled on the server. In a multi server environment, these steps should be performed on the proxy node
* You should have a signed certificate + matching key pair and the trusted chain certs from your CA (Certificate Authority) (This is a common issue, so please, make sure you check your files before deploying them)
* You can bind Multiple SSL Certificates to just one ipv4 address, which will pair to the respective domain names. For example:
  1.1.1.1 => example.com
  1.1.1.1=> otherdomain.com
and you could even have another IPv4 address, for Customer reasons with other group of SSL Certificates, even different type of SSL Certificates:
  3.3.3.3 => yetanotherdomain.com (A Comodo Wildcard SSL Certificate)
  3.3.3.3 => thisisanotherdomain.com (A free Let's Encrypt SSL Certificate)
  3.3.3.3 => customer001.net (A RapidSSL Certificate)
  etc.

===Browser support for SNI===
The following browsers do offer support for SNI, however Zimbra hasn't tested all of them, it is the responsibility of the web-browser, to support the application part of SNI  :
{|class="wikitable sortable"
! Software !! Type !! Supported !! Notes !! Supported since
|-
| Internet Explorer || Web browser || <i class="fa fa-check-circle"></i> || Since version 7 on Vista (not supported on XP) || 2006
|-
| Mozilla Firefox || Web browser || <i class="fa fa-check-circle"></i> || Since version 2.0 [https://bugzilla.mozilla.org/show_bug.cgi?id=116169#c26 Reference 116169] || 2006
|-
| curl || Command-line tool and library || <i class="fa fa-check-circle"></i> || Since version 7.18.1 || 2008
|-
| Safari || Web browser || <i class="fa fa-check-circle"></i> || Not supported on XP ||
|-
| Google Chrome || Web browser || <i class="fa fa-check-circle"></i> || Since 6.0 || 2010
|-
| BlackBerry OS || Web browser || <i class="fa fa-check-circle"></i> || 7.2 or later ||
|-
| Windows Mobile || Web browser ||<i class="fa fa-check-circle"></i> || Some time after 6.5<ref>{{cite web|url=http://blogs.msdn.com/b/ieinternals/archive/2009/12/07/certificate-name-mismatch-warnings-and-server-name-indication.aspx |title=Understanding Certificate Name Mismatches |publisher=Blogs.msdn.com |date= |accessdate=2011-03-08}}</ref> ||
|-
| Android default browser || Web browser || <i class="fa fa-check-circle"></i> || Honeycomb (3.x) for tablets and Ice Cream Sandwich (4.x) for phones<ref>{{cite web|url=https://code.google.com/p/android/issues/detail?id=12908 |title=Android issue 1290 - Https websites that support Server Name Indication (SNI) don't work |publisher=Code.google.com |date=2010-12-01 |accessdate=2011-12-13}}</ref> || 2011
|-
| wget || Command-line tool || <i class="fa fa-check-circle"></i> || Since version 1.14 || 2012
|-
| Nokia Browser for Symbian || Web browser || <i class="fa fa-times"></i> ||   ||
|-
| Opera Mobile || Web browser || <i class="fa fa-times"></i> || Not supported on Series60 ||
|-
|}

==Configuring the IP address per domain==
* 1.  Add the new domain, in this case '''example.com'''. Set '''zimbraVirtualHostName''' to '''mail.example.com''' and '''zimbraVirtualIPAddress''' to '''1.2.3.4'''. Make sure the zimbraVirtualHostName is set to the name which will be used to access the domain (URL) and the SSL certificate is signed for the same name.
  zmprov md example.com zimbraVirtualHostName mail.example.com zimbraVirtualIPAddress 1.2.3.4

'''NOTE: If the server is behind a firewall and NAT'ed with an external address, make sure external requests for "mail.example.com" hit the aliased IP address and not the actual local IP address of server.'''

==Verifying and Preparing the Certificates==
We should have three files received from the CA (might vary depending on the Certificate Authority). The server (domain) certificate, and two chain certs. Also, you should have an existing key file (which was used to generate the csr)
* 1.  Save the '''example.com certificate''', '''key''' and '''chain files''' to a directory '''/tmp/example.com.''' You can receive single or multiple chain certs from your CA. Here we have two chain certs from the CA. i.e. example.com.root.crt and example.com.intermediate.crt.
  ls /tmp/example.com
  example.com.key
  example.com.crt
  example.com.root.crt
  example.com.intermediate.crt

* 2.  Add the chain certs to a single file called example.com_ca.crt
  cat example.com.root.crt example.com.intermediate.crt >> example.com_ca.crt

* 3.  Confirm if the key and certificate matches and chain certs completes the trust. As zimbra user:
  /opt/zimbra/bin/zmcertmgr verifycrt comm /tmp/example.com/example.com.key /tmp/example.com/example.com.crt /tmp/example.com/example.com_ca.crt


** Check the output, it should say something like this. If not, make sure you have the correct key and chain cert files.
 ** Verifying '/tmp/example.com.crt' against '/tmp/example.com.key'
 Certificate '/tmp/example.com.crt' and private key '/tmp/example.com.key' match.
 ** Verifying '/tmp/example.com.crt' against '/tmp/example.com_ca.crt'
 Valid certificate chain: /tmp/example.com.crt: OK

==Deploying the Certificate or Certificates on the domain==
* 1.  Add the domain certificate and chain files to a single file called '''example.com.bundle'''
  cat example.com.crt example.com_ca.crt >> example.com.bundle

* 2.  Run the following command as the '''zimbra''' user to save the certificates and key in LDAP:
  /opt/zimbra/libexec/zmdomaincertmgr savecrt example.com example.com.bundle example.com.key
 ** Saving domain config key zimbraSSLCertificate...done.
 ** Saving domain config key zimbraSSLPrivateKey...done.
**  The syntax is:
  /opt/zimbra/libexec/zmdomaincertmgr savecrt <domainname> <certificate with chain certs> <keyfile>

* 3.  Run the following command as the '''zimbra''' user to deploy the domain certificate. This will save the certificate and key as '''/opt/zimbra/conf/domaincerts/example.com''':
  /opt/zimbra/libexec/zmdomaincertmgr deploycrts
 ** Deploying cert for example.com...done.

== Proxy Check ==
Run these commands on proxy hosts, or on the server if it's Single Server: 
* zimbraReverseProxySNIEnabled should be set to TRUE in server and global config. 
 zmprov mcf zimbraReverseProxySNIEnabled TRUE

== Re-write and restart Proxy ==
*  Restart the proxy to re-write the changes to proxy config
  zmproxyctl restart

*  Once the restart is successfull, try to access the domain using the URL which is set in "zimbraVirtualHostName" over https. And check the certificate loaded in the browser. In this case the URL will be https://example.com

=Testing=
You can go now to a Web browser and check that for each different '''zimbraVirtualHostName''', you see a different SSL certificate and that its details are correct for that virtualhostname.

=Troubleshooting=
* If you do not see the correct domain cert by accessing the domain with its zimbraVirtualHostName (example.com). Make sure that the https connection from the Internet/intranet is going to the server's local IP address which is defined in '''zimbraVirtualIPAddress''', and make sure you have activated '''zimbraReverseProxySNIEnabled''' to '''TRUE'''

* If you are using multiple proxy servers or adding new proxy servers, make sure you copy all the contents of '''/opt/zimbra/conf/domaincerts/''' to all the proxy servers. '''Otherwise the proxy service will fail to start.'''

=Known Issues=
* [https://bugzilla.zimbra.com/show_bug.cgi?id=102913 Bug 102913 - '''Multiple SSL domains on single server (SNI) for HTTPS connections''']
* [https://bugzilla.zimbra.com/show_bug.cgi?id=103362 Bug 103362 - '''Multiple SSL domains on single server (SNI) for IMAPS/POP3S connections''']

{{Article Footer|Zimbra Collaboration Suite 8.7|03/05/2016}}
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