Best Linux mail servers in 2023

A mail server is a software which is used for transferring emails on the internet from one point to another. It is an important component of the email communication system, it is a specialized software application that manages the sending, receiving, and storing of email messages. Mail servers are fundamental to email servers and play an important role in the exchange of electronic mail between users and organizations. While sending an email from their email client, the email client then communicates with the user’s outgoing mail server, often referred to as the SMTP (Simple Mail Transfer Protocol) server. When the recipient mail server (MTA) receives an incoming email, it uses DNS to look up the recipient’s mail server’s address based on the domain in the recipient’s email address.

The mail server generally operates using mail protocols like:

1. POP3 (Post Office Protocol 3)
2. IMAP (Internet Message Access Protocol)
3. SMTP (Simple Mail Transfer Protocol)

In simple terms, a mail server is a digital post office for emails, it is software that manages the receiving, sending, and storing of email messages.

Working of Email Server

Why mail servers are required?

The mail server provides instant email delivery over the internet, where the system of information storage is organized. It also provides security and privacy of your mail and performs email marketing campaigns more effectively. Businesses must host a mail server of their own, which ensures reliable delivery of mail and reduces the chances of undelivered mail.

Choosing the right Linux Mail Server as per your requirement?

When selecting a mail server there are many things you need to consider:

1. The primary factors in choosing a mail server are the features it offers and how well it meets your requirements.
2. Another important factor is the size of your organization. If you have a small business with only a few users, then a small mail server is all you need, but if you have a large amount of users you must approach for powerful server.
3. Another factor is the cost of the server and whether or not it will fit into your budget.

Best Linux Mail Servers in 2023

1. Postfix

Postfix is a popular and widely used Linux mail server, it is designed to handle the routing and delivery of email messages. It is known for its performance, security, and simplicity. If you want an open-source MTA then you should consider postfix.

It was first developed by Wietse Venama, a Dutch-American computer scientist and researcher. It was developed mainly focusing on security, robustness, and high performance. Postfix was first released in 1997 as an alternative to Sendmail MTA.

Features:

• It is robust, maintainable, secure, simple, and easy to configure.
• It has built-in spam protection.
• It supports virtual domains and user configurations, which makes it suitable for hosting multiple email domains and users within a single server.
• Postfix also supports IPv6, ensuring that it can work in networks that use the latest Internet Protocol version.

2. Exim

Exim stands for “Experienced Internet Mailer”, and is also a popular and widely used Linux mail server, which is widely known for its flexibility, and stability which makes it a versatile choice for email administrators. Exim was originally developed at the University of Cambridge, it supports mainly Unix-like operating systems.

Exim is an Open-Source MTA and is widely used in email server configuration due to its flexibility, robustness, and extensive features.

Features:

• Exim’s configuration can be made from a simple text file that can be customized to meet specific server requirements. Which makes it more flexible as compared to other Mail servers.
• Exim provides various security features to protect against spam, it supports many authentication mechanisms such as encryption, and access control.
• It generates detailed logs that can be used for diagnosing email delivery issues and monitoring email performance.
• It also supports Queue Management which ensures reliable delivery of email.
• It has high efficiency as compared to other MTAs as it can handle large volumes of email traffic efficiently.

3. Dovecot

Dovecot is an open-source Linux Mail server, it is also a versatile Mail Transfer Agent as it can be installed on various Unix-like operating systems. Dovecot is an MDA (Mail Delivery Agent), IMAP (Internet Message Access Protocol), and POP (Post Office Protocol) server.

Dovecot is an Open-Source computer application and is compatible with both individuals and businesses but for large businesses, it is recommended to use its commercial version “OX Dovecot Pro” as it supports more business features and can handle more mail traffic reliably, it is also known for its cross-platform compatibility.

Features:

• Dovecot supports IMAP and POP3 mail protocols, which allow email clients to access and retrieve mail stored on the server.
• It can handle large mailboxes and high numbers of email clients efficiently.
• Dovecot is highly configurable and allows system administrators to set up various email policies and access controls.
• It also supports security features like authentication mechanisms such as encryption, and access control.
• Dovecot can also be used with MTAs (such as Exim or Postfix) and other email-related components, such as anti-spam and anti-virus software which proves the integration facility.

4. Sendmail

Sendmail is one of the earliest and most widely used Mail Transfer Agent (MTA) in the Unix and Linux world. It serves as the software responsible for routing and delivering email messages within a network, making it a critical component of email systems. It was released under an open-source license.

Sendmail is known for its flexibility, and simple configuration, it is a powerful and versatile mail server. It mainly uses SMTP email protocol which makes it an SMTP server that is reliable for sending email. Sendmail was developed by Eric Allman, an American computer programmer. It was first released in the late 1970s.

Features:

• Sendmail supports various extensions and add-ons, such as milters (Mail Filter API).
• It supports a mailing list function.
• It is still actively maintained and developed with new features.
• It also supports encryption protocols and is more flexible.

5. OpenSMTPD

OpenSMTPD was developed by Gilles Chehade, a French-born computer programmer and one of the key contributors to the OpenBSD project. It can be used as an alternative to other popular MTAs like Sendmail, Postfix, and Exim.

If you have more email traffic then OpenSMTPD is the best option and it is a free and open-source mail transfer agent (MTA) software used for routing and delivering email messages on Unix-like operating systems. It was originally developed as part of the OpenBSD project and is designed to be secure, simple to configure, and efficient. OpenSMTPD focuses on providing a secure and reliable email infrastructure.

Features:

• It is mainly designed for simple and secure emailing.
• It is designed to be resource-efficient and can handle a large amount of email traffic.
• It is modular and can be customized according to the user’s needs.
• It also supports portability and can be used on many Unix-like operating systems.

6. Zimbra

Zimbra is also one of the widely used MTAs when it comes to mail servers, Zimbra provides two editions. Zimbra Community Edition which is a free and open-source mail server. Zimbra Commercial Edition which is a paid version and has numerous amounts of features that support scalability and more customizability.

It is not the traditional MTA but a comprehensive collaboration and email server software suite. It is mainly used for large-scale businesses and thus has a user-friendly webmail interface.

Features:

• It supports File Sharing.
• It is highly available and scalable.
• Security and encryption.
• It supports real-time chat and messaging systems.

7. Citadel

Citadel was developed by Citadel Project, citadel is one of the open-source Linux mail server software, it supports various features like receiving and delivering email messages. It is designed to be reliable, scalable, and efficient which makes it more suitable for both small- and large-scale businesses.

It is designed to provide integrated email, calendaring, address book, bulletin board, and other groupware features. Citadel’s architecture and functionality can be similar to a traditional email server, but it extends its capabilities to offer collaboration and groupware features.

Features:

• It supports SMTP protocol.
• It supports multiple user management within the server.
• It is open-source; hence it is customizable to one’s needs.
• Citadel manages the email delivery queue, ensuring that messages are sent and received efficiently and reliably.
• It also supports security features like spam and virus filtering.
• It has multi-domain support and virtual hosting.
• User can also maintain an address book within Citadel, which make it easy for the user to manage contact information and share it with others in the group.

8. Mail-in-a-Box

Mail-in-a-Box is an open-source email server software package that allows individuals and small organizations to easily set up and configure their email servers. It was created with a focus on user-friendliness and is designed to run on various Unix-like operating systems, such as Ubuntu and Debian.

It is easy to set up, and an all-in-one solution, it not only includes mail services but also provides, spam filtering, DNS configuration, and many more, it also focuses on security and privacy it configures SSL/TLS encryption by default and its spam filtering helps in protecting unwanted emails. It also supports features like DNS integration which ensures that the mail sent from the user is properly routed.

Features:

• It has a webmail interface.
• Spam and virus protection.
• It has built-in security features like SSL/TSL encryption.
• It supports automatic updates.

9. iRedMail

iRedMail is an open-source, free email server solution that simplifies the task of deploying and managing mail servers. It provides a full-featured email solution. It is designed for a Unix-like operating system. It is mainly suitable for small to medium-sized businesses.

For maintaining large-scale businesses iReadMail offers iRedAdmin-Pro as it supports features like unlimited account, domain level admin, antispam, and multilanguage support which are useful for businesses but at the same time, they are all paid features and can be integrated with iRedMail. iRedMail is compatible with Unix-like OS such as CentOS, Debian, Ubuntu, FreeBSD, and OpenBSD.

Features:

• It has a browser-based interface.
• It has database support for storing user and domain information.
• It comes with a web-based admin panel.
• It has built-in security features like antispam and antivirus.

10. Apache James

Apache James, also known as the Apache Java Mail Enterprise Server, is an open-source email server and application suite developed by the Apache Software Foundation. It provides a set of email-related services and protocols for building and managing email systems, including POP3, IMAP, SMTP, and more. Apache James is written in Java which makes it a cross-platform mail server.

The Apache James project has an active community and user base, providing resources, documentation, and support for users and administrators. It supports various security features such as SSL/TLS encryption for secure mail communication, it is also robust and flexible, and it also offers mail storage Apache James can store emails and user data in a variety of backends, including file systems, databases, and more. Apache James is designed with a modular and extensible architecture, making it highly customizable and versatile to various email functions.

Features:

• It is actively maintained and developed by the community.
• It has cross-platform compatibility.
• It offers a security feature to secure the user data.
• It enables mail routing to ensure messages get delivered to the right recipients.
• It also provides a mail storage facility.

Conclusion

In Conclusion, Linux is a better platform as it is supported by the community. And with a lot of Open-Source Linux-based Mail Servers, it is difficult to choose one for yourself. But depending on your requirements, and budget you can choose the best one from the above list. Most importantly all the software in the list is open source, so you don’t need to trust someone else, you can take a sneak at the code yourself, and ensure its safety.