Microsoft Exchange Server Alternatives for Linux

Zentyal is a comprehensive open source server solution based on Ubuntu, providing critical network services such as email, groupware, file sharing, and network infrastructure roles like directory services and gateway functions, all managed through an intuitive web interface.

Kolab Community is a comprehensive, free, and open-source groupware suite designed for collaborative work. It provides integrated email, calendar, contacts, and tasks functionalities, empowering individuals and teams to communicate and manage their data efficiently and with a strong focus on data privacy.

SOGo is a powerful open-source groupware server designed for scalability and simplicity. It provides a comprehensive suite of collaborative features including webmail, calendaring, contact management, and task management, with strong support for standard protocols like CalDAV and CardDAV.

Zimbra Collaboration Suite is a comprehensive open source email and collaboration platform designed for businesses. It provides a secure and feature-rich environment for email, calendaring, contacts, tasks, and file sharing, supporting on-premises and cloud deployments.

Kopano is a versatile open-source groupware suite offering email, calendaring, contacts, and online collaboration tools for businesses and organizations. It provides flexible deployment options, including on-premises and hosted solutions, with strong focus on data privacy and security.

Zarafa is an open-source groupware and email server platform, providing powerful collaborative features similar to Microsoft Exchange but with flexibility and cost advantages. It offers email, calendaring, contacts, and task management.

iRedMail is a comprehensive, free, and open-source mail server solution designed for ease of deployment and maintenance. It bundles popular components like Postfix, Dovecot, and Roundcube, providing robust email, calendar, and contact management capabilities.

mailcow is a comprehensive open-source mail server suite built on Docker, providing a robust and secure platform for self-hosting email. It integrates various components like Postfix, Dovecot, and SOGo into a single, easy-to-manage system.

OX Open-Xchange is a comprehensive web-based suite designed for communication, collaboration, and office productivity, offering features like email, calendaring, task management, and document sharing, seamlessly integrating across devices.