46 Like Zentyal Good alternative? YES NO Zentyal is a native Microsoft Active Directory® implementation on Linux incorporating all the network services required in a small and medium business environment:... Free Open Source Linux No features added Add a feature
34 Like Kolab Community Good alternative? YES NO Kolab Groupware is a secure, scalable, reliable, flexible, full-featured collaboration suite. Free Open Source Linux Web Self-Hosted CalDAV CardDAV Real time collaboration Support for WebDAV Add a feature
19 Like hMail Server Good alternative? YES NO 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... Free Open Source Windows POP3 Support Add a feature
27 Like Zimbra Collaboration Suite Alternative? YES NO Zimbra Collaboration is an open, secure collaboration tool for email, calendaring, tasks and more. With the most innovative web application available today, Zimbra... Freemium Linux Web Real time collaboration Add a feature
26 Like SOGo Good alternative? YES NO 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... Free Open Source Linux Web Thunderbird Cloudron CalDAV CardDAV Add a feature
5 Like SophiMail Good alternative? YES NO SophiMail is a fully-featured email and collaboration server solving the most critical email issues: maximizes Privacy, Portability and Cost efficiency, Admin & User... Free BSD VirtualBox Self-Hosted VMware vSphere Hypervisor Daily Backup Indexed search CalDAV CardDAV ... Data portability Privacy focused Private messaging Schedule Backup Security focused Selective folder sharing Shared folders Team Collaboration Two factor authentication Unlimited users Add a feature
16 Like iRedMail Good alternative? YES NO 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... Free Open Source Linux BSD Self-Hosted No features added Add a feature
16 Like mailcow: dockerized Good alternative? YES NO 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. Free Open Source Linux Support for Docker Add a feature
10 Like OX Open-Xchange Good alternative? YES NO Open-Xchange Server 6 is the most advanced Linux based Groupware solution f. Open-Xchange Server 6 is superior in the following areas: • Open-Xchange Server 6 offers... Free Open Source Linux Web Real time collaboration Support for WebDAV Add a feature
4 Like Citadel Good alternative? YES NO 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... Free Open Source Linux Web Real time collaboration Add a feature
7 Like OpenChange Good alternative? YES NO OpenChange aims to provide a portable Open Source implementation of Microsoft Exchange Server and Exchange protocols. Exchange is a groupware server designed to work... Free Open Source Linux No features added Add a feature
5 Like Blue-Mind Good alternative? YES NO Blue Mind is a complete solution of company messaging, calendars and collaborative work. It aims to enable you to work daily with comprehensive, useful, efficient and... Free Open Source Linux ActiveSync Reduce mobile data usage Add a feature
3 Like Sendmail Good alternative? YES NO Sendmail is a general purpose internetwork email routing facility that supports many kinds of transfer and delivery methods, including the Simple Mail Transfer Protocol... Free Open Source Mac Linux No features added Add a feature
3 Like OBM Good alternative? YES NO OBM is a free messaging and collaboration platform useful for just a couple to many thousands of users with strong support for mobile devices. Free Open Source Mac Windows Linux CalDAV Real time collaboration Add a feature
3 Like Mercury Mail Transport System Alternative? YES NO The Mercury Mail Transport System is a mail server that sends and receives messages on behalf of a group of users on a machine or local area network. Messages from the... Free Personal Windows No features added Add a feature
