What is Carbonio?#

Zextras Carbonio is the fully private digital workplace, which consists of:

  • E-mail, Contacts and Calendar Essentials, all shareable across a domain

  • A complete mailserver, equipped with anti-spam and anti-virus software

  • Chat and Videochats

  • File Management System including collaborative editing and document sharing

  • Tasks

Strong points of Carbonio include:

  • focus on Data Sovereignty and Privacy

  • simplicity to install as Linux packages and ready to use out of the box

  • comprehensive set of enterprise-level collaboration and communication features

  • scalability: set up a single-server, then easily add nodes as company’s infrastructure and needs grow

Browser Compatibility#

All Carbonio features are accessible from a browser: the supported browser are listed in Table 1.

Table 1 List of supported browsers#





Google Chrome




Mozilla Firefox




Mozilla Firefox




Microsoft Edge (Chromium)




Microsoft Edge (Chromium)




Mozilla Firefox




Google Chrome












Microsoft Edge (EdgeHTML)




Internet Explorer




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


We suggest to always use the latest version available of the browser.

Available Languages#

Carbonio's main language is English; the Web GUI is available in these languages

Officially included languages
  • English (GB, US, AU)

  • Dutch

  • French

  • German

  • Hindi

  • Indonesian

  • Italian

  • Japanese

  • Brazilian Portuguese (BR)

  • Russian

  • Spanish

  • Thai

Community supported languages
  • Polish

  • Turkish

  • Hungarian

  • Vietnamese

Volunteer Translators#

Zextras makes available an online translation platform to qualified individuals wishing to help the translation process.

Translation in languages that are not currently supported is encouraged, albeit we cannot guarantee any estimate upon the official inclusion in the product.

Please contact for any information on the topic or to volunteer as a translator.

Contribution to the Documentation#

The source code of Carbonio‘s documentation is now available in a public repository hosted on Github.

We are happy to accept any kind of documentation, written according to the guidelines, in form of a pull request. In case you have an idea for the documentation or you do not feel confident using Python Sphinx (the framework we use for writing documentation), you can send an e-mail to the address .

Seeking Help on Carbonio#

Besides this documentation, Zextras makes available the following online resources:


Zextras Community is a collection of articles, guidelines, howtos, and other useful material about Zextras products, including Carbonio, whose dedicated section is

Official Discussion Forum

The Official Forum is the place where the community members interact, search for useful resources, provide own feedback, share their experiences, or comment articles. Carbonio has its own section

Open a Ticket

If you are a Carbonio customer you can open a support ticket on Zextras support portal, located at To allow for a quicker response from our support team, make sure to include in your ticket all relevant information related to your problem.

How to report an issue#

Whenever a problems arise while using a software, resolving them and going back to the normal daily activities as quick as possible is always the first goal.

Therefore, the most efficient way to report a Carbonio issue is the one that allows both the Reporter and the Technical Support Team to reach their common goal in the quickest and more robust way.

To do so, the starting point is to prepare an accurate and complete report that describes the issue experienced, then open a ticket on Zextras customer’s support portal and attach the report to the ticket. This allows the Technical Support Team to immediately look into the issue without asking for more information.

Building a detailed report may require one or more of the following activities:

  • to describe the steps that allow to reproduce the problem. This is the most important point, because this would give the Technical Support Team a first idea about the possible root cause of the issue.

  • to execute commands from the CLI

  • to prepare screenshots

  • to carry out other tasks that depend on the issue reported, the modules involved, and so on.

Before You Open a Ticket#

Before you open a Support Ticket, you should gather some information and configuration values from Carbonio and its Components, to collect the information that will be relevant for the Technical Support Team.

This section focuses on how to retrieve this information: You need to provide existing log files and the output of some commands and scripts (see next sections) that need to be executed from the command line. Please note that, unless stated otherwise:

  • In the case of Multi-Server installations, commands must be executed on the node where the Component is installed

  • Log files are located under the /opt/zextras/log/ directory


Remember that the most information you are able to provide, the quicker the Technical Support Team will help you restore the everyday activities of your Carbonio installation.

Issues, enquiries, or complaints with licensing

While at Zextras we do our best to provide the fairest licensing model possible, we know it may not fit for every customer. If you feel that the Zextras Licensing does not suit your needs and wish to let us know your opinion, please contact the Sales Team through the form you can find at

General And Common Information#

The general and common information are needed in every case: this kind of data allows to understand the scenario in which the issue was experienced. You need to save the output of each of the following commands to a text file.

zextras$ zmcontrol -v
zextras$ carbonio --host all_servers core getVersion
zextras$ carbonio core getLicenseInfo
zextras$ zmprov gas
zextras$ zmprov gas mailbox
zextras$ systemctl status carbonio-*
zextras$ journalctl


To save the output of to a text file, you use the > operator, for example

zextras$ zmcontrol -v > zmcontrol.txt

An additional task that help the Technical Support Team is to enable debug logging, then attach to the ticket the log files generated:

  1. increase the log verbosity on the mailbox server by running

    zextras$ carbonio config server set $(zmhostname) \
    attribute ZxCore_LogLevel value 0
  2. Reproduce the issue

  3. Restore the normal log verbosity by running

    zextras$ carbonio config server set $(zmhostname) \
    attribute ZxCore_LogLevel value 1

Once done, the log files to attach are:

  • mailbox.log file from the mailbox server

  • The nginx.log and the nginx.access.log files from the Proxy Node

Mobile And Mobile Apps#

Follow these steps on an e-mail account and a mobile device, then attach the log files that will be produced during the procedure.

  1. Activate an account logger in debug mode on one of the affected devices using the command

    zextras$ carbonio mobile doAddAccountLogger user@domain.tdl
    debug /path/to/log/file.log
  2. Remove the account from the device

  3. Add the account on the device again

  4. Try to reproduce the issue

Files and information to attach
  • The mailbox.log and the sync.log files

  • A brief explanation of how to reproduce the issue

  • Manufacturer, model and exact OS version of the mobile device

  • The output of the following commands, making sure to replace the uppercase parameters with the e-mail account and the ID of the device

    zextras$ carbonio mobile getDeviceList JACK.SMITH@ACME.EXAMPLE
    zextras$ carbonio mobile getDeviceInfo JACK.SMITH@ACME.EXAMPLE DEVICEID

Carbonio Chats#

In you experience problems with Carbonio Chats, collect the output of the following commands. Replace JACK.SMITH@ACME.EXAMPLE with one affected account. You can also set up a test account without Administrator privileges and repeat the commands.

zextras$ carbonio config dump global
zextras$ carbonio chats clusterStatus
zextras$ carbonio chats getServices
zextras$ carbonio chats iceServer get
zextras$ for cos in $(carbonio prov gac); do carbonio prov gc $cos; done
zextras$ carbonio prov ga JACK.SMITH@ACME.EXAMPLE
zextras$ for cos in $(carbonio prov gac);
do echo $cos;
carbonio config cos get $cos;
zextras$ carbonio config account get JACK.SMITH@ACME.EXAMPLE
zextras$ for dom in $(carbonio prov gad);
do carbonio prov gd $dom zimbraPublicServiceProtocol \
zimbraPublicServiceHostname zimbraPublicServicePort;
zextras$ carbonio powerstore getAllVolumes

Also attach to the ticket the following files.

  • the mailbox.log file relative to a restart of the mailboxd with zmmailboxdctl restart

  • the mailbox.log, the zmmailboxd.out, the nginx.log and nginx.access.log files relative to the last two days

Carbonio Files#

In case of issues with Carbonio Files, provide the output of this script

zextras$ for dom in $(carbonio prov gad);
do carbonio prov gd $dom zimbraPublicServiceProtocol
zimbraPublicServiceHostname zimbraPublicServicePort;

Also provide the /var/log/carbonio/files/files.log and /var/log/carbonio/docs-connector/docs-connector.log files

Carbonio Storage#

In the case of Carbonio Storage, you need to provide also some information about the storage infrastructure (volumes, disks) of Carbonio

zextras$ mount
zextras$ df -h
zextras$ df -i

Then, collect information about the configuration of Carbonio Storage

zextras$ carbonio powerstore getAllVolumes
zextras$ carbonio powerstore getHsmPolicy
zextras$ carbonio powerstore getMovedMailboxes
zextras$ carbonio powerstore getNonLocalMailboxes
zextras$ carbonio config dump server $(zmhostname)

Carbonio Backup#

Like for Carbonio Storage, first get a few environmental information

zextras$ mount

Then find the Backup Path and other configuration:

zextras$ ls -l $(carbonio config dump server $(zmhostname) | grep ZxBackup_DestPath | tr -s ' ' | cut -d ' ' -f 3)
zextras$ carbonio config dump server $(zmhostname)
zextras$ carbonio backup getBackupInfo

Client-side issues#

In case you experience a client-side issue, follow this procedure to collect the relevant information:

  • Open a new browser (Chrome or Firefox) window

  • Open the Javascript Console (Ctrl + Shift + j on Windows and Linux, Cmd + Opt + j on OSX)

  • Access the webmail from the same tab the Javascript Console has been opened on

  • Wait for the webmail to load completely

  • Reproduce the issue

  • Go to the Console tab of the Javascript Console, right-click anywhere and select Save as… to save the content of the tab as a text file

  • Go to the Network tab of the Javascript Console, right-click anywhere and select Save as HAR with content to save the content of the tab as a text file

  • Attach both files with the console export and the network export to the ticket.