Top 20 Best Open Source Email Servers for Windows / Linux

Top 20 Best Open Source Email Servers for Windows / Linux. Are you on the lookout for the perfect open source email server software but haven’t a clue where to start? In this post, we’ve done all that hard work for you. There is a thorough evaluation of the top email servers in terms of performance, security and user-friendliness. There is pros, cons, and quirks of each software. 

Shall we start with article Top 20 Best Open Source Email Servers for Windows / Linux?

Top 20 Best Open Source Email Servers for Windows / Linux

1. Postfix

Postfix, an open-source mail transfer agent (MTA). Notably, Postfix is known for its prioritization of security, ensuring confidentiality, integrity, and protection of emails. Overall, Postfix is a reliable email server that gives access to extensive configuration options.

Pros of Postfix

  • Secures your email with spam filtering, TLS encryption, and a variety of authentication mechanisms
  • Allows you to handle large volumes of email traffic and adapt to growing demand.    
  • Vibrant and active community of users and developers. 
  • Customize it to meet your needs. 
  • Excellent email filtering options. 

Cons of Postfix

  • The email filtering processes is memory hungry. 
  • Lack of a GUI.

2. Zimbra

Zimbra, an open-source email and collaboration software. Comes with a wide selection of communication and productivity tools. Get an email, calendar, contacts, file sharing, tasks, and other collaboration features in one package. Moreover, Zimbra works with Linux and Windows and offers a web, mobile, and desktop interface. As a result, access your emails from anywhere, using any device.

Pros of Zimbra

  • Wide selection of tools that enhance productivity and simplify communication. 
  • Access Zimbra from anywhere with a variety of platforms and devices. 
  • Comes with a modern user interface. 
  • Use Zimbra for both small organizations and large ones. It grows with your team. 
  • Opt for high-availability configurations that guarantee continuous access to emails and other tools. 
  • Comes with spam and virus filtering, encryption, and two-factor authentication to keep emails secure. 

Cons of Zimbra

  • Need technical expertise to set up Zimbra. 
  • Limitations when you want to integrate third-party tools or customize the functionality. 

3. iRedMail

iRedMail is designed to simplify the process of deploying a feature-rich email system on Linux. In the package, you get a complete suite of reliable and widely-used software components for managing your email. Also, you get to choose where you store mail accounts between OpenLDAP, MySQL, MariaDB, and PostgreSQL. Owing to its versatility, you  tailor the email system to your specific needs and preferences.

Pros of iRedMail

  • Setting up a complete mail server is a straightforward process. 
  • Integrations with other mail server software components is seamless.
  • iRedMail comes with a web-based admin panel to manage email configurations. 
  • Your email is secured with spam filtering, antivirus scanning, and support for SSL/TLS encryption.

Cons of iRedMail

  • Customization options are limited.
  • Limited official support options. 
  • Updates may be an issue since iRedMail depends on a bundle of various open-source tools whose updates aren’t synchronized.
  • iRedMail is not built for scalability. 

4. Modoboa

Designed for LinuxModoboa provides a web based interface for managing multiple email domains, users, aliases, and other features. Additionally, it’s easy to integrate Modoboa with popular software like Dovecot and Postfix. In conclusion, Modoboa harnesses the power of Python and employs an SQL database to integrate all these components.

Pros of Modoboa

  • Rich set of features, including support for multiple domains, user roles, integrated webmail, and advanced filtering capabilities.
  • Clean and user-friendly web based interface. 

Cons of Modoboa

  • Relatively new, so it has a smaller user community than the competition. 
  • Lacks proper documentation. 

5. Roundcube

Another choice of Top 20 Best Open Source Email Servers for Windows / Linux is Roundcube. Designed to offer a seamless and intuitive email experience through a web browser. Read, compose, and organize emails efficiently, making it a versatile solution for both personal and professional use. Supports multiple email protocols, including IMAP and SMTP, allowing you to connect to various email servers. Although Roundcube is primarily developed for Linux, install and configure it to work on Windows as well.

Pros of Roundcube

  • Enables you to compose emails with HTML formatting.
  • With built-in spell check, Roundcube helps ensure your emails are free from spelling errors.
  • Offers a convenient drag-and-drop feature, making it easy to organize your emails into folders and categories.
  • Extend the functionality through third-party plugins.
  • Simplifies message composition with email templates.  

Cons of Roundcube

  • Limited search functionality, allowing you to search for only one item at a time.
  • Occasionally, Roundcube’s address book may experience occasional crashes.
  • You may experience timeout issues with large mail folders.

6. Citadel

Developed with simplicity and efficiency in mind, Citadel offers a user-friendly interface and powerful features to enhance your email experience. This open-source email server runs primarily on Linux and provides a “Web 2.0” interface along with SMTP, IMAP, POP3, and GroupDAV access to its content. Compose, send, receive, and organize emails effortlessly, making communication a breeze.

Pros of Citadel

  • Regular backups of documents.
  • Comes with antivirus and antispam features to keep your emails and documents secure.
  • User-friendly interface that makes it easier for your to manage your email.
  • Good documentation.

Cons of Citadel

  • Complex configuration.
  • Clunky user interface. 

7. SquirrelMail

SquirrelMail, one of the most renowned Linux mail servers, supports both the IMAP and SMTP protocols. Developed in PHP and released under GNU, it provides a user-friendly interface and a simple setup process. With its reliability, scalability, and efficient performance in handling large mail volumes, SquirrelMail is an ideal choice if you need a straightforward tool. It prioritizes security through features like SSL encryption and spam filtering, while seamlessly integrating with popular web hosts and platforms such as WordPress.

Pros of SquirrelMail

  • Acts as an IMAP protocol proxy server, facilitating seamless email access and retrieval.
  • Search and flag emails.
  • SquirrelMail includes a built-in spell checker.
  • User friendly interface for easy email management.
  • Store and manage your email addresses in SquirrelMail’s address book feature.

Cons of SquirrelMail​

  • Lacks support for HTML composition.
  • The user interface often gets buggy.  
  • No security updates since 2013. 

8. Apache James

Apache James, also known as Java Apache Mail Enterprise Server, works seamlessly on both Linux and Windows environments. Its modular architecture and modern components make it a robust platform for efficient email management. Supports multiple protocols such as SMTP, POP3, LMTP, IMAP, and ManageSieve. Easy to integrate with third party systems. Other additional features are: Mailbox API, command-line admin, and extendable email processing agents, providing you with enhanced flexibility and customization options.

Pros of Apache James

  • Easy to integrate with various mail clients and systems.
  • Allows for flexibility and customization to meet specific email server requirements.
  • Designed to run on a wide range of popular operating systems, including Windows, macOS, and Linux.
  • Designed to handle high volumes of email traffic efficiently, ensuring smooth operation even in demanding environments. 

Cons of Apache James

  • You may find the documentation less comprehensive or organized.

9. Mail-in-a-Box

Mail-in-a-Box is designed for individuals and small businesses who want full control over their email hosting. With Mail-in-a-Box, handle everything from sending and receiving emails to robust spam filtering and convenient webmail access. Some of its core features include automatic DNS configuration, spam filtering, grey listing, backups to Amazon S3, static website hosting, and simple SSL certificate installation.

Pros of Mail-in-a-Box​

  • Straightforward installation process, easy for users with limited technical knowledge.
  • Offers the convenience of obtaining free TLS (SSL) certificates from Let’s Encrypt.

Cons of Mail-in-a-Box​

  • The user interface of Mail-in-a-Box might be considered outdated or lacking modern design elements.

10. hMailServer

hMailServer is a popular open source email server software designed for Windows and Linux. It provides a robust and feature-rich solution for managing email accounts, domains, and messaging services. It supports popular protocols like POP3, IMAP, and SMTP ensuring compatibility with various email clients. Plus, hMail Server provides essential features such as spam protection, virus scanning, and customizable email processing rules. 

Pros of hMailServer

  • Intuitive admin interface that makes it easy to set up, configure, and manage email accounts and domains.
  • Comes with a flexible native rules builder to create custom rules for customizing how hMail handles your mail. 
  • Compatible with a wide range of email clients. 
  • In-built spam protection and antivirus scanning. 

Cons of hMailServer

  • Setting up proper security measures requires advanced knowledge and experience in email server administration.

11. Axigen

Axigen is a comprehensive email platform Linux and Windows based. Intuitive web-based interface allows you to manage emails, calendars, contacts, tasks, and more. Even better, you do all this from any device. Whether you’re a small business or a large enterprise, Axigen offers scalability and flexibility to adapt to your growing needs. AEnjoy advanced features like integrated antivirus and antispam protection, SSL/TLS encryption, and seamless collaboration. With Axigen’s robust administration capabilities, you have full control over users, domains, and server settings.

Pros of Axigen

  • Simple setup and user-friendly interface make it easy to use. 
  • Comes with a convenient address book for easy contact management. 
  • Highly configurable platform suitable for customization.

Cons of Axigen

  • Availability and responsiveness of support may vary depending on the chosen support package or subscription level. 
  • No subscription fees depending on your plan. 

12. Exim

Exim is great for a reliable, flexible, and scalable mail transfer agent (MTA). It’s widely recognized for its versatility and is commonly used on UNIX-like systems, including Linux, as the default MTA. With Exim, you have access to a wide range of advanced features and configuration options. This makes it suitable for both small-scale and large-scale email systems. Exim supports various protocols like SMTP and offers robust security measures such as access controls, TLS encryption, and spam filtering. The extensive documentation and active community support make Exim an excellent option for those seeking a customizable and powerful email server.

Pros of Exim

  • Exim is a reliable, consistent, and efficient email server.
  • Extensive config and customization options.
  • Suitable for both small and large-scale email systems with in-built scalability.
  • Comes with robust security features.

Cons of Exim

  • No graphical interface for admin so you have to rely on command-line tools.

13. Dovecot

Another on our list of Top 20 Best Open Source Email Servers for Windows / Linux is Dovecot. It comes with an impressive array of features that enhance email management. With support for both IMAP and POP3 protocols, users access their emails from various devices and email clients. Dovecot supports multiple mailbox storage formats, including mbox and Maildir. Fast and efficient indexing enables quick searching and retrieval of emails, even with large archives. The integration of SSL/TLS encryption ensures secure email communication, while seamless integration with anti-spam and anti-virus software enhances security and protects against malicious threats.

Pros of Dovecot

  • Easy extensibility through plugins.
  • Security features, including encryption, authentication, and SSL/TLS protocols.
  • Handles a large number of mailboxes and seamlessly scales to meet the growing needs of your organization.

Cons of Dovecot

  • Dovecot lacks an extensive built-in web interface for admin and management.
  • For webmail, Dovecot requires integration with other software or services, which may add complexity to the setup.

14. Open-Xchange

Open-Xchange is a collaborative software suite combining email, calendar, contacts, and other productivity tools into a unified platform. It enhances teamwork and communication and provides a seamless and integrated environment for managing and sharing information. Works with both Linux and Windows. 

Pros of Open-Xchange

  • The integrated calendar feature allows you to schedule appointments, set reminders, and share your availability with colleagues.
  • Supports synchronization with mobile devices to access emails on the go.
  • Intuitive and user-friendly interface.
  • Integration with other tools to enhance functionality is seamless.

Cons of Open-Xchange

  • Limited customization options for email settings and configurations. 
  • Relies on other software components, such as a mail transfer agent (MTA) like Dovecot, to handle the actual email delivery and retrieval.
  • Lacks advanced functionalities such as setting complex email rules or specific email filtering options.

15. MailCow

Mailcow (also known as “mailcow: dockerized”) is an open-source, self hosted mail server. It utilizes Docker containers to provide a modular and scalable architecture that allows you to deploy and maintain an email server environment. Mailcow uses tools such as Postfix, Dovecot, SpamAssassin, and Roundcube, among others, to handle various aspects of email processing, storage, spam filtering, and webmail interface. 

Pros of MailCow

  • Simplified setup and management due to the Dockerized architecture. 
  • Docker’s scalability allows Mailcow to scale seamlessly.
  • Includes essential mail server components like Postfix, Dovecot, SpamAssassin, and Roundcube.
  • User friendly web interface.

Cons of MailCow

  • Docker introduces an additional layer of abstraction, which may impact the performance of the Mailcow containers.
  • Relies on various components and dependencies, such as database systems and web servers, which need to be properly configured and compatible with the Mailcow containers.

16. Mailu

Mailu is an open-source, self-hosted email server solution that offers a simplified and flexible approach to managing your email infrastructure. Focuses on security and runs on Linux-based systems, Mailu comes with features like SMTP, IMAP, POP3, webmail access, spam filtering, and more.

Pros of Mailu

  • Straightforward setup process and intuitive web interface.
  • Customize various aspects of their email server, including spam filtering, antivirus settings, authentication mechanisms, and more.
  • Prioritizes security and privacy, incorporating features like SSL/TLS encryption, DKIM signing, SPF validation, and advanced spam filtering.

Cons of Mailu

  • Mailu’s web interface focuses on functionality rather than visual aesthetics. 
  • Limited out-of-the-box integrations with third-party services and applications.
  • Setting up and configuring Mailu  is challenging for users with limited experience. 

17. Haraka

Haraka is an open source and highly scalable email server software running on Unix systems (Linux and macOS). Harnessing the power of JavaScript, Haraka delivers exceptional performance, making it an ideal choice for handling large volumes of email. With its modular design and extensive plugin support, you customize and enhance Haraka to meet your specific email server needs. Enjoy features like spam filtering, TLS encryption, and support for various protocols. 

Pros of Haraka

  • Exceptional speed and scalability. Suitable for high-volume email environments.
  • Easy customization and extension with plugins.
  • Lightweight architecture ensures efficient email processing, optimizing resource usage and delivering fast performance.
  • Supports various email protocols such as SMTP, ESMTP, and LMTP, ensuring compatibility with different email clients and systems.

Cons of Haraka

  • You might need JavaScript programming experience to set up Haraka. 
  • The extensibility of Haraka heavily relies on plugins.
  • Focuses on command-line interaction so you won’t have access to a GUI.

18. combines all the essential email server components, from SMTP to webmail, into a cohesive, easy-to-use package. Easily configure and manage multiple domains and users. Also, get access to advanced features like spam filtering, antivirus protection, and secure communication through TLS encryption.

Pros of

  • Spam filtering and antivirus scanning capabilities.
  • Provides secure communication through TLS encryption.

Cons of

  • May not scale as efficiently for large-scale email environments or organizations with significant email traffic.
  • No command-line or advanced configuration options. 

19. SOGo

SOGo, short for Scalable, combines email, calendar, contacts, and task management into a comprehensive email suite for Linux. With support for industry-standard protocols like CalDAV, CardDAV, and IMAP, SOGo seamlessly integrates with your favourite email clients and devices. Access your emails, schedules, and contacts from anywhere through its intuitive web-based interface.

Pros of SOGo

  • SOGo is scalable, allowing it to accommodate the growing needs of organizations.
  • Seamless integration with Mozilla Thunderbird and Lightning using the SOGo Connector and SOGo Integrator.
  • Offers ActiveSync compatibility, allowing synchronization of email, contacts, calendars, and tasks with mobile devices.
  • Modular and extensible architecture to add custom features and integrate with external systems through APIs.

Cons of SOGo

  • SOGo can be resource-intensive.
  • Limited out-of-the-box integrations with third-party applications.

20. Mailpiler

Mailpiler is a Linux-based email archiving and retrieval software that facilitates secure storage, indexing, and easy access to email messages. Easily locate and retrieve specific email messages, saving you valuable time and effort. Even better, you have access to advanced features like comprehensive search capabilities, tamper-proof storage, and deduplication. As a result, enforce retention policies, comply with legal requirements, and efficiently handle e-discovery requests.

Pros of Mailpiler

  • Offers fast and responsive email archiving and retrieval.
  • Handles large volumes of email data, providing scalability as your email archives grow.
  • Advanced search features enable precise and quick retrieval of specific emails based on various criteria.
  • Helps you ensure compliance with data retention laws and data privacy and protection regulations.  

Cons of Mailpiler

  • Configuring Mailpiler may require technical expertise.
  • Customization options are limited, restricting the ability to tailor it to unique organizational needs. 

Thank you for reading Top 20 Best Open Source Email Servers for Windows / Linux. We shall conclude the article. 

Top 20 Best Open Source Email Servers for Windows / Linux Conclusion

Choosing the right email server for your organization is crucial for efficient communication and productivity. In our comprehensive post, we have highlighted the pros and cons of each email server, giving you valuable insights to make an informed decision. Whether you prioritize reliability, scalability, security, user-friendliness, or specific functionalities, there is an open-source email server that aligns with your requirements.

Avatar for Richard Kanyoro
Richard Kanyoro

The world’s biggest problems can be solved by progressively solving the little ones. I write to help people solve the “little” tech problems they face.

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