Legal notice & attributions

Publisher

This documentation is published by

grommunio GmbH
Donau-City-Straße 7 / door 2 / 30th floor (DC Tower)
1220 Vienna, Austria

Managing director: Norbert Lambing
Commercial register: FN 538037g, Handelsgericht Wien
VAT identification number: ATU75763639
Telephone: +43 1 375 0108

The complete legal notice of the company, including the contact addresses, supervisory authority and dispute-resolution information, as well as the privacy policy and the general terms and conditions are maintained on the company website:

Copyright and licence

Unless stated otherwise, the text of this documentation is licensed under the Creative Commons Attribution-ShareAlike 4.0 International licence (CC BY-SA 4.0) or, at your option, any later version of that licence. You may copy, redistribute and adapt it, including for commercial purposes, as long as you credit grommunio GmbH, link to the licence and distribute derived material under the same licence.

The sources of this documentation are maintained at github.com/grommunio/grommunio-documentation. Corrections and additions are welcome as pull requests or issues.

The Man Pages section, the Gromox internals & specs, Gromox wiki and Project setup pages of the Development set, the grommunio-admin command reference and the Admin API reference are generated automatically from the source repositories of Gromox and grommunio admin-api; the Project setup pages additionally reproduce the READMEs of grommunio-web, grommunio-sync, grommunio-dav, admin-web and grommunio-index. They are reproduced here under the licences of those projects; see the LICENSE files in the respective repositories.

Screenshots show grommunio and third-party software as it appeared at the time of writing. The user interfaces of the products depicted may have changed since.

Disclaimer

grommunio GmbH prepares this documentation with care, but cannot guarantee that every statement is accurate, complete or up to date. Commands, configuration snippets and procedures are provided as examples for the described environment; they may require adaptation to your installation and must be tested before being used on a production system. Always keep a current backup before you change a running system. Use of the documentation is at your own risk; to the extent permitted by law, grommunio GmbH accepts no liability for damage resulting from its use.

External links point to content of third parties over which grommunio GmbH has no control. The respective operators are responsible for that content; at the time of linking no illegal content was recognisable. If you become aware of a legal problem with a linked page or with any part of this documentation, please contact us so that we can react.

Support entitlements arise from a grommunio subscription or support contract only; this documentation does not create any warranty or support obligation.

Trademarks

grommunio and the grommunio logo are registered trademarks of grommunio GmbH. gromox is a trademark of grommunio GmbH.

Amazon Web Services, AWS, Amazon EC2, EC2 and related marks are trademarks of Amazon.com, Inc. or its affiliates in the U.S. and/or other countries.
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DRBD and LINBIT are trademarks or registered trademarks of LINBIT in Austria, the United States and other countries.
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Kerberos is a trademark of the Massachusetts Institute of Technology (MIT).
Kerio and Kerio Connect are trademarks or registered trademarks of GFI Software or its affiliates in the U.S. and other countries.
Keycloak is a trademark of The Linux Foundation in the United States and/or other countries.
Kubernetes, Prometheus, Xen Project and The Linux Foundation are registered trademarks of The Linux Foundation. Additional trademarks are listed at https://www.linuxfoundation.org/trademark-list/.
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The MariaDB mark is a trademark of MariaDB Corporation Ab; the mariadb.org, MariaDB Foundation and MariaDB Server marks are exclusively licensed to the MariaDB Foundation.
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Nextcloud is a trademark of Nextcloud GmbH.
nginx is a trademark of F5, Inc.
ONLYOFFICE is a trademark of Ascensio System SIA.
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OpenLDAP is a registered trademark of the OpenLDAP Foundation.
ownCloud is a trademark of ownCloud GmbH.
Red Hat, CentOS, RHEL and Red Hat Enterprise Linux are trademarks or registered trademarks of Red Hat, LLC or its subsidiaries in the United States and other countries.
Redis is a registered trademark of Redis Ltd.
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Ubuntu and Canonical are registered trademarks of Canonical Ltd.
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Valkey and the Valkey logo are trademarks of LF Projects, LLC.
VMware, vSphere, vSAN and ESXi are trademarks or registered trademarks of Broadcom Inc. and/or its subsidiaries in the United States and other jurisdictions.
Zimbra is a registered trademark of Synacor, Inc.

All other trademarks, trade names, service marks and company names referenced in this documentation belong to their respective owners, foundations or development communities. Their use is for identification only and does not imply endorsement.

Third-party contributions

grommunio GmbH thanks the people and projects whose work this documentation builds on.

forgeone.solutions

The Setup guides (post-installation checklist, antispam, single sign-on with Keycloak, Meet, Chat, Files & Office, Archive, mobile devices, backup and restore), the IMAP migration with imapsync page and the failover-testing sections of the High availability chapter draw on the German field-guide series grommunio 2026 Schritt für Schritt published by forgeone.solutions. Its author kindly permitted the re-use of that material, which was restructured, generalised and verified against a grommunio appliance for this documentation. The lab measurements quoted in the high-availability chapter were taken by forgeone.solutions.

The original articles:

Upstream projects

The reference sections are kept in sync with the documentation shipped by the Gromox project (man pages, protocol specifications, wiki) and the grommunio admin-api project (command reference and OpenAPI specification). The Project setup pages reproduce the READMEs of those two projects and of grommunio-web, grommunio-sync, grommunio-dav, admin-web and grommunio-index. The many contributors to those projects are credited in the respective repositories.

The IMAP migration with imapsync page describes imapsync by Gilles Lamiral, which grommunio ships as the imapsync package; its option and exit-code tables summarise the imapsync README, which, like the tool itself, is published under the No Limit Public License (NLPL).

Community

Corrections, questions and real-world experience shared in the grommunio community forum and as issues and pull requests on GitHub continuously improve these pages. Thank you.

Documentation toolchain

This site is built with free and open-source software:

Component	Purpose	Licence
Astro	Static site framework	MIT
Starlight	Documentation theme, navigation, i18n	MIT
Starlight built-in icon set, derived from Unicons by IconScout	User-interface, sidebar-topic and card icons	IconScout Simple License
starlight-openapi and starlight-sidebar-topics by HiDeoo	Admin API reference pages; topic switcher	MIT
Pagefind	Full-text search	MIT
Expressive Code with Shiki	Code blocks and syntax highlighting	MIT
Mermaid	Architecture diagrams	MIT
astro-icon with the Iconify icon sets Lucide (ISC) and Circle Flags (MIT)	Theme switcher icons and language flags	MIT / ISC
Playwright driving Chromium	Headless rendering of diagrams and PDF exports; extraction of rendered pages for the EPUB export	Apache-2.0 / BSD-3-Clause
pandoc	Conversion of man pages and reStructuredText sources; EPUB export	GPL-2.0-or-later
sharp	Image processing	Apache-2.0
Noto Sans — Copyright 2022 The Noto Project Authors (github.com/notofonts/latin-greek-cyrillic)	Typeface, served as self-hosted subset WOFF2 files (modified version)	SIL Open Font License 1.1

The English pages are the authored originals. Pages in other languages are machine-translated with the DeepL API and may contain translation errors; where a translation is missing, the English text is shown.