Zextras Docs


Zextras Docs is based on a heavily customized LibreOffice online package allowing for collaborative editing of documents, spreadsheets and presentations straight from the Zimbra WebClient.


Zextras Docs is not compatible with Zimbra version 8.8.11 and lower.


Zextras Docs Server

The Zextras Docs server is the heart of the service. The service hosts each document opened through a LibreOffice engine and responds to the client via an image upon every keystroke and change in the document.


This component must be installed on one or more dedicated nodes running Ubuntu 16.04 LTS, Ubuntu 18.04 LTS or Red Hat Centos 7.

Zextras Docs Extension

The extension is the key component which coordinates everything. Its main tasks are:

  • Select which Docs server the next document will be opened on.

  • Redirect the client when it needs to open a document.

  • Read and write documents to and from system storage on behalf of the Docs server.

  • Connect to each Docs server via an administrative websocket and keep track of the availability and the resource usage of each.

  • Orchestrate concurrent user connections to the same document in the same server. (document sharing)

The Zextras Docs Extension is contained within the Zextras Core component of Zextras Suite.

Zextras Docs Zimlet

A Zextras Docs Zimlet handles the integration with Drive items and with email attachments. It is a thin web client which connects to a native server instance via websocket, renders a document and only sends changes to the client in order to keep the fidelity of the document on par with a desktop client while at the same time reducing the bandwidth to the bare minimum.

Documents in preview and attachments are shown in read-only mode with a simplified interface, while edit mode has a full interface.

Its main tasks are:

  • Change the “create” button in the ZWC to the related Docs feature.

  • Change the preview feature to use Docs.

  • Allow the preview of documents.

Minimum System Requirements

Following are the minimum system requirements to install Zextras Docs server:

  • Centos 7, Ubuntu 16.04, or Ubuntu 18.04

  • At least 2 CPU cores

  • At least 4 GB RAM

  • At least 4 GB free disk space

Browser compatibility

The following list shows which browsers are known to fully support all Zextras features.





Microsoft Edge (Chromium)




Microsoft Edge (Chromium)




Microsoft Edge (EdgeHTML)




Internet Explorer




Mozilla Firefox




Mozilla Firefox




Mozilla Firefox




Google Chrome




Google Chrome












Items marked as “ Limited” are only supported on the browser’s two previous stable releases.

Document Management Flow

This is what happens “behind the scenes” when a user creates a new document:

  1. The Zimlet prompts the Extension to create a new empty document

  2. The Extension creates the document and returns the document’s ID to the client

  3. The Zimlet opens a new Zimbra tab containing an iframe pointing towards ‘/service/extension/wopi-proxy’

  4. The extension receives the request from the client, creates a new token for the needed document, and replies with a new url

  5. The new url points toward /docs/[docs-node-id]/[token], which will be proxied by nginx to the specific Docs Server node

  6. The Docs Server will respond with the web application in Javascript

  7. The web application opens a websocket connection, going through the nginx

  8. Docs Server receives the websocket connection along with a token, sends a read wopi command towards the mailbox url indicated in the parameters (the url is validates against allowed nodes)

  9. The Extension validates the token and replies with information and content

  10. The Docs Server node parses the document, renders it and sends it back to the client.

  11. The document is fully opened and editable.

Open document
                                  redirect to docs
    +------------------------+             +----------------------+
    |     Zimbra Proxy       |             |       Mailbox        |
    |                        +------------->                      |
    |      Nginx             |             | Zextras Docs Extension|
    +------------------------+             +----------------------+
                      |                        |              ^
                      |                        |              |
                      |                        |             WOPI:
                      |                   Admin Web          Read/Write
                      |                   Socket             Documents
                      |                        |              |
                      |                        |              |
                      |                        |              |
                      |                    +---v----------------+
                      |                    |                    |
                      +-------------------->   Docs Server      |
                   Load Client             |                    |
                   Open client websocket   +--------------------+

Networking and ports

All mailbox servers will need to be able to directly communicate with the Docs Server over port 8443 (HTTPS Backend), which must be open on both ends.

The Docs Server communicates with the Extension through port 9980, so incoming traffic from all mailbox and proxy servers to that port must be allowed. The Docs Server component must also be able to directly communicate with the master LDAP server as well as with all Proxy servers.

Installation and Configuration


This component must be installed on one or more dedicated nodes running Ubuntu 16.04 LTS, Ubuntu 18.04 LTS or Red Hat Centos 7.

Docs Nodes

Download the zextras-docs.tgz standalone installer for your distribution (Centos 7 | Ubuntu 16 | Ubuntu 18), extract it and as the root user execute the install.sh script contained in the package.

To obtain the information required for the initial Docs Server setup, run the following command on any mailbox server:

zimbra@mbx1:~$ zmlocalconfig -s ldap_master_url zimbra_ldap_user zimbra_ldap_userdn zimbra_ldap_password

This will return the info you need in the following format:

ldap_master_url = ldap://ldap01.cfd6a9e5.test.example.com:389
zimbra_ldap_user = zimbra
zimbra_ldap_userdn = uid=zimbra,cn=admins,cn=zimbra
zimbra_ldap_password = Deyked4ofMarj

The script will install the Zextras Docs package and then ask the information about the master ldap, url, username and password, which will be used to add a new server in the LDAP with just the ‘docs’ service installed/enabled. Every Docs Server will be visible by every node, and will read the LDAP in order to write the configuration in /opt/zimbra/conf/docs/loolwsd.xml.

Once the setup is completed no other configuration is needed.

Mailbox Nodes

While the Zextras Docs extension is already contained within Zextras Suite, the com_zextras_docs Zimlet needs to be deployed on the server and enabled on all users and COS that need to have access to the Zextras Docs features.

The com_zextras_docs Zimlet can be deployed from the “Core” section of the Zextras Adminictration Zimlet.

No configuration on the mailboxd side is needed after the Zimlet has been deployed and enabled.

Proxy Nodes

The proxy configuration must be re-generated after adding one or more Zextras Docs Servers to the infrastructure: to do so, run /opt/zimbra/libexec/zmproxyconfgen as the zimbra user and then restart the proxy service running zmproxyctl restart as the same user.

The new docs nodes will be read from ldap and no manual configuration is needed.


Zextras Docs is included in every Zextras Suite Pro license..

The standalone installer is released under the MPLv2 license while the extension and Zimlet are released under a proprietary license.


Before uninstalling the software the node must be removed form LDAP either from the docs node via command:

zdocs remove-local-server

or via the zmprov command from any zimbra node:

zmprov deleteServer {servername}


Zextras Docs Server CLI - zdocs

On Docs server zdocs (/usr/local/bin/zdocs as root) command can generate the config for lool (it’s already on cron), add/remove the docs server from ldap, test configuration and manage the service.

``zdocs`` command.

usage: zdocs [-h] [--auto-restart] [--ldap-dn LDAP_DN] [--ldap-pass LDAP_PASS]
             [--ldap-url LDAP_URL] [--hostname HOSTNAME] [--debug][--cron]


Manage Zextras Docs service.

Available commands:
  genkey                Generate a private key needed for authentication between docs and mailbox servers.
  write-local-server    Add or update in LDAP the necessary server entry for this server in order to be reachable from other servers.
  remove-local-server   Remove local server entry in LDAP.
  generate-config       Populate the config template with ldap values and write a new configuration file.
  ldap-write-config     Write new configuration about the ldap access needed to generate the docs configuration file.
  ldap-test             Check the ldap connection.
  start                 Start the service.
  stop                  Stop the service.
  restart               Restart the service.
  status                Print service status.
  setup                 Start the initial setup.

positional arguments:

optional arguments:
  -h, --help            show this help message and exit
  --auto-restart        Automatically restart the service if configuration is changed (to be used with generate-config)
  --ldap-dn LDAP_DN     Ldap dn (distinguish name) to bind to (to be used with ldap-test and ldap-settings)
  --ldap-pass LDAP_PASS Ldap password used of the DN (to be used with ldap-test and ldap-settings)
  --ldap-url LDAP_URL   Ldap url completed with schema (ex.: ldaps://ldap.example.com, to be used with ldap-test and ldap-settings)
  --hostname HOSTNAME   Hostname of this server (to be used with add-local-server)
  --debug               Show complete errors when things go bad.
  --cron                Start in cron mode, avoid any output unless there is an error (to be used with generate-config).

#regenerate the config and restart the server if config changed
  zdocs --auto-restart generate-config
#restart the service
  zdocs restart
#check ldap connection availability using current settings
  zdocs ldap-test
#check ldap connection using custom settings
  zdocs --ldap-url ldaps://ldap.example.com/ --ldap-dn 'uid=zimbra,cn=admins,cn=zimbra' --ldap-pass password ldap-test
#change the ldap connection settings
  zdocs --ldap-url ldap://ldap2.example.com/ --ldap-dn 'uid=zimbra,cn=admins,cn=zimbra' --ldap-pass password
#add the local server
  zdocs write-local-server
#add the local server with a custom hostname in LDAP, this command should be already invoked during setup.
  zdocs --hostname myhostname write-local-server
#remove the local server from LDAP, useful when destroying the server, you can also use 'zmprov deleteServer' from a mailbox server.
  zdocs remove-local-server

Zextras Docs Extension CLI - zxsuite docs

On a Mailbox server, the zxsuite docs command is available. This command allows to check and control the Docs service’s status, to force a configuration reload and to see the Docs Servers’ status. Please refer to section Zextras Docs CLI.


Nothing happens when opening a document / extension requests returns 503

This is most likely due to a connection issue between the mailbox server and the Docs server. Check the mailbox.log and see the reason for the connection failure. If there are no connection errors, check the Docs server with zdocs status on the docs node.

The mailbox will log every connection and disconnection for each Docs server.

404 error code instead of docs

The proxy configuration needs to be re-generated and the proxy restarted

Docs opens but a message “this is embarrassing…​” appears instead of the document

This happens if the Docs server cannot connect back to the mailbox server to read and write the document. Check name resolution and SSL certificate of mailboxd which must be valid for the Docs server that does not inherit Zimbra certificate management.

Zextras Docs CLI

This section contains the index of all zxsuite docs commands. Full reference can be found in the dedicated section ZxDocs CLI Commands.

This section contains the index of all zxsuite auth This section contains the index of all the available zextras docs commands. Full reference can be found in the dedicated section.

doDeployDocsZimlet doReloadConfig doRestartService doStartService doStopService getServices status