This Administrator Manual covers everything regarding installation, operation and maintenance of the grommunio software suite. The intended audience for this documentation is administrators and system operators deploying grommunio.


grommunio delivers a fully-featured communication solution which covers all aspects of the software-defined era. As a modern and modular platform, grommunio helps to simplify all needs of modern communication by providing the following feature set:

  • E-Mail

  • Calendar

  • Contacts

  • Tasks

  • Notes

  • Video meetings

  • Chat

  • File sync & share

  • Web office

Overview & Concepts

grommunio is shipped as an integrated software appliance for deployment on target systems by combining an embedded, optimized operating system, based on openSUSE. While grommunio is also shipping software repositories for major Linux platforms, the software appliance allows quick deployment on a variety of platforms, including bare metal and virtualized environments.


grommunio's software component stack is modular and consists of the following main components:



Component Group

gromox-delivery, gromox-delivery-queue

Local delivery agent that places messages received from Postfix into mail stores

grommunio Groupware


Software bus inter-process communication (IPC) mechanism that allows communication between multiple processes running concurrently on multiple machines.

grommunio Groupware


The mail store (exmdb), and HTTP interface for RPCH, EWS, and optional FastCGI passthrough

grommunio Groupware


IMAP interface providing industry-leading performance to IMAP clients

grommunio Groupware


POP3 interface

grommunio Groupware


Bridge process between PHP-MAPI and exmdb

grommunio Groupware


Message index database, mostly an acceleration mechanism for use by IMAP

grommunio Groupware


grommunio-antispam not only keeps your mail service clean from spam but also provides interfaces for anti-virus scanning and filtering

grommunio Groupware


A REST interface for automation and which provides the main API for grommunio's administration web interface

grommunio Admin


grommunio-admin-web is the central administration interface for system, domain and user management

grommunio Admin


grommunio-web is the user's main web interface delivering a rich user experience to browser-based clients

grommunio web service


grommunio-sync provides the main EAS (Exchange ActiveSync) service for native clients, such as iOS, Android and other EAS-capable clients

grommunio web service


grommunio-dav provides the main CardDAV and CalDAV service for native clients, such as macOS and other capable clients

grommunio web service


grommunio-files provides the file sync and share functionality, available to web and native clients

grommunio Files


grommunio-chat provides the main enterprise chat functionality, available to web and native clients

grommunio Chat


grommunio-meet is the web-based enterprise meeting feature, available to web and native clients

grommunio Meet


grommunio-office is the web-based document collaboration software suite, available to web clients

grommunio Office


grommunio-archive delivers a legally conform archiving solution, available to web clients

grommunio Archive

Other software components used in combination with grommunio:

  • MariaDB is the central database for all user metadata which provides the main database for all backend services. No user payload data (e-mails, etc.) are stored in this database.

  • Postfix provides world-class functionality and versatility as the de-facto standard MTA which allows even the most advanced mail routing setups.

  • nginx is a fast, robust and modern web server acting as the main web server and providing major services via HTTP and RPC to clients.

  • SQLite is used for storage of the individual users' mailbox stores.

Some parts of grommunio are shipped as forks of other successful open source software. While grommunio only ships the open variants (with some integration features added), many of these open source vendors deliver enterprise variants of their software components. If the software component is covered by the grommunio subscription, grommunio delivers support for the open source variants of these components as well. Using the enterprise variants of the respective vendors is supported from an integration perspective, yet not for the vendors' product.

At grommunio, the top priority is to deliver a seamless communication and collaboration experience for users and a turnkey installation experience for administrators. These ambitions have led to the inclusion of other software components with additions (such as authentication through a single stack). This way, the integration effort for administrators is kept low, while users benefit from the interaction of multiple software components, delivering a seamless experience.

As a reference, the components of software products forked as part of the grommunio stack are:

  • grommunio-files is a fork of Nextcloud with authentication and setup enhancements (

  • grommunio-meet is a fork of Jitsi with integration enhancements (

  • grommunio-office is a fork of OnlyOffice web with integration enhancements (

  • grommunio-chat is a fork of an open source chat platform with authentication and integration enhancements

  • grommunio-archive is a fork of Piler with authentication and integration enhancements (

  • grommunio-antispam is a fork of rspamd with integration enhancements (

grommunio maintains and integrates these software solutions with the delivery targets offered by grommunio, such as software appliance and well-packaged software components available for all major Linux distributions. All these components are fully supported by grommunio based on the respective subscription level.

In case an environment or similar installation exists, these components can be integrated on an interface level. Note that grommunio can not support installations not packaged by grommunio. However, if existing enterprise installations are available, the integration of these systems is possible with the correct configuration in place. grommunio subscriptions deliver support for integrations with these enterprise variants or even - based on the interfaces available - alternative solutions.

grommunio delivers a variety of interfaces which allow other solutions to integrate with grommunio. Because of the modular nature of grommunio's software distribution, there is no forced need to use the extra components delivered by grommunio. For turnkey solutions, especially in the SMB market, shipping these components with the simplified integration effort helps administrators to install and operate grommunio as a comprehensive communication platform within just a few minutes.