The best open source alternative to Microsoft Exchange is mailcow: dockerized. If that doesn't suit you, our users have ranked more than 25 alternatives to Microsoft Exchange and 15 is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Microsoft Exchange are Kolab, hMail Server, Zentyal and grommunio.
mailcow is a mail server suite based on Dovecot, Postfix, SOGo, Rspamd and other open source software, that provides a modern Web UI for administration.
mailcow: dockerized is the most popular Self-Hosted alternative to Microsoft Exchange.
mailcow: dockerized is the most popular Open Source & free alternative to Microsoft Exchange.
Kolab provides a FOSS communication & collaboration solution that can be completely self-hosted. Take back control of your data and access it via the webinterface, or existing mobile & desktop clients.
hMailServer is a free e-mail server for Microsoft Windows. Its used by Internet service providers, companies, governments, schools and enthusiasts in all parts of the world.
Integrates native Active Directory and all essential network services, including domain, mail, gateway, infrastructure, and security roles, for SMBs, offering web-based management, centralized authentication, file server, VPN, and firewall in a single Linux platform.
Not an Exchange alternative at all. Does basic AD but that is about it. It is more of a gateway server.
They do not share any common functionality. Zentyal is an Active Directory substitute, Microsoft Exchange is a groupware E-Mail (enterprise grade) server.
Some users think Zentyal is a great Microsoft Exchange alternative, some don't.
grommunio (formerly known as grammm) efficiently combines all requirements of modern, digital communication and collaboration.
Great Activesync Support POOR and I mean VERY Poor Calendar that has a mind of It's own, setting events or reminders is a NIGHTMARE
As the first open source solution to offer a full-featured OutlookAnywhere (RPC over HTTP) and MAPI/HTTP implementation, grammm is the alternative to proprietary backends for native interoperability with Microsoft Outlook
Almost everyone thinks grommunio is a great Microsoft Exchange alternative.
grommunio is the most popular iPad alternative to Microsoft Exchange.
SOGo is groupware server with a focus on scalability and open standards.
SOGo provides a rich AJAX-based Web interface and supports multiple native clients through the use of standard protocols such as CalDAV, CardDAV and GroupDAV.Share your calendars, address books and mails in.
Kolab Now provides a suite of intuitive apps in a user friendly environment to make your day to day online comms easier, smarter and most importantly; secure.
With Microsoft no longer supporting our existing setup, this was a great alternative.
Some users think Kolab Now is a great Microsoft Exchange alternative, some don't.
The OX App Suite by Open-Xchange is web-based platform offering a suite of apps like an email client, calendar, contacts magement, cloud storage with synchronization and productivity apps for word processing, spreadsheets and presentations.
A fully fledged, free email server solution, an open source project (GPL v2).
Use official binary packages from Linux/BSD distributions, with both i386 and x86_64 support.
Easy, fast deployment in LESS THAN 1 MINUTE. View YouTube Video to check how easy it is.
Works on both no.
OpenChange aims to provide a portable Open Source implementation of Microsoft Exchange Server and Exchange protocols.
Is a collaboration suite (messaging and groupware). It is designed to run on open source operating systems such as Linux or BSD. In order to modernize the Citadel platform for the Internet, the Citadel/UX developers added functionality such as shared calendars, instant...
Web-based team collaboration suite combining email client, calendar, contact and task tools, CRM, project and file management, file sharing, trouble tickets, Rocket.Chat chat, and Collabora online editing. Offers open source, self-hosted, and SaaS options.
Germany
EU
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Canada
No Exchange alternative and no support for MS Outlook Client