Top 10 Best Mail Transfer Agents (MTA) For Linux Servers

Top 10 Best Mail Transfer Agents (MTA) For Linux Servers. In this article we will introduce what MTA is and we will introduce top mail transfer Agents in Linux environment. 

What is Mail Transfer Agent (MTA)

Email is one of the fastest source of communication over the Internet. Many companies and businesses rely on email to transfer their messages to one another. On the network node, there are email clients that help transfer messages to and from email servers using SMTP server but are not MTA. These are Mozilla Thunderbird, Apple Mail, Evolution, Microsoft’s Outlook set up on a mail client (user computer).

A Mail Transfer agent is software that plays a key role in the Internet message handling system. It uses SMTP to transfer and route electronic mail messages from one system to the other. It has a client/server architecture and is installed on a mail server.

A message transfer agent (MTA) is a software application used within an Internet message handling system (MHS) which transfers and routes an electronic mail message from the sender’s computer to the recipient’s computer. A message transfer agent is a mail relay that receives incoming emails and forwards the messages to individual clients/users.

As email has proved to be a vital and reliable source of communication, it is essential to choose the right mail transfer agent that fulfills all your needs. Here, we have listed some of the top MTA’s on Linux mail servers.

1. Sendmail

Sendmail, also known as Proofpoint, is one of the oldest and most popular MTA on the Linux server platforms that uses TCP or IP networks following SMTP protocols to transfer and receive messages. Installed on an email server, it only sends email.

It is lightweight, fully configurable and a reliable source that administrators can manage remotely. Along with multiple advantages, it also has certain limitations. The configuration process is complex, it supports weak security mechanisms and does not have Post Office Protocol (POP) or Internet Message Access Protocol (IMAP).

There is many alternatives to Sendmail available online but it is one of the most popular MTA.

Features of Sendmail

  • The lightweight and fully configurable MTA is suitable for large and complex environments.
  • Sendmail is a highly portable solution.
  • Flexible and easy to use.
  • Supports UNIX System V mail and Internet mail.
  • Makes use of configuration files for controlling and managing mail configuration.
  • Allows creating own mailing lists.
  • Offers failure messages to a client if an error is found in transferring messages to the recipient.
  • Requires minimum server resources to run the software.

2. Postfix

Postfix is a free, open source, cross platform server initially designed as an alternative to Sendmail MTA. Wietse Zweitze Venema designed and developed this cross platform while working on a project at the IBM research department. The purpose was to design software that may cover up the drawbacks of the Sendmail and help in determining routes and sending emails.

It offers simple administration, a secure operation mechanism, easy configuration and flexibility in working. Also, it is fast in performance and compatible with Linux machines, Mac OSX, and other Unix like operating systems.

Features of Postfix

  • Junk mail control.
  • Offers Database and Mailbox supports.
  • Supports numerous protocols.
  • Compatible with UNIX like systems.
  • Address manipulations and offers multiple layers of defense.
  • Postfix is fast, flexible, and robust MTA.
  • UCE control.
  • Uses table lookups.

3. Exim

Exim is one of the most used and free MTA designed under the GNU General Public License terms for Unix like operating systems. It is an open source MTA with outstanding mechanisms and features.

Users can easily view historical messages, all outgoing and incoming message queues. Also, the MTA allows users to monitor all incoming emails and offers flexibility in routing mails.

Features of Exim

  • Supports RFC 2821 SMTP and RFC 2033 LMTP email message transport protocols.
  • Access control lists.
  • Supports content scanning.
  • Configurations and encryption.
  • Routing Control features.
  • Does not support POP and IMAP protocols.
  • Supports utilities like Lemonade to enable mobile messaging.
  • It has a retry section to define the message that got failed to deliver at the first attempt.
  • Includes header and envelope rewriting facilities.
  • Allows users to view historical messages, all outgoing and incoming message queues.

4. Qmail

Next on the list of Top 10 Best Mail Transfer Agents (MTA) For Linux Servers is qmail.It is a secure, free, open source mail transfer agent (MTA) designed to run on Unix like operating systems. It is an alternate MTA for Sendmail with high security features. It is a totally modular system quicker than Sendmail and can handle bulk mail actions.

Moreover, it is a simple, reliable and efficient MTA that offers full support for address groups, VERPs. Also, the software provides automatic per host configuration.

Features of Qmail

  • Qmail is free, open source MTA and is quick to install.
  • Allows users to easily create and manage their own mailing list.
  • Supports VERPs.
  • Qmail is compatible with Unix like operating systems.
  • Supports address groups.
  • Offers automatic prevention of mailing list loops.
  • Ezmlm mailing list manager support.
  • Does not support random lists.
  • It forestalls mailing list circles.

5. Mutt – Command Line Email Client

Mutt is another text based email client, small yet powerful for Unix like operating systems. It comprises some of the best features and allows users to send and read emails from the command line. User friendly software with a strong and active development community.

Another feature that makes it a top choice is Mutt supports POP and IMAP protocols. It also provides Delivery status support and the facility of a mailing list. The terminal based email client supports message threading and tagging. Also, the design is compatible with maildir, mbox, MH, and MMDF mailbox formats.

Features of Mutt

  • Message threading.
  • Offers Delivery status support.
  • IMAP and POP3 protocol support
  • Supports PGP/MIME (RFC2015).
  • It has a strong and active development community.
  • Mutt is easy to install email client compatible with Unix like operating systems.
  • Easy configuration.
  • Allows users to add attachments from the command line.
  • Users can add BCC (Blind carbon copy) and CC (Carbon copy) in the mails.
  • It provides a mailing list facility.
  • Supports maildir, mbox, MH, and MMDF mailbox formats.
  • Compatible with minimum of 20 languages.
  • Offers DSN (Delivery Status Notification) support.
  • Allows users to reply or forward multiple messages at once.
  • Enables multiple message tagging.
  • Allows automatic change of configuration.

6. Alpine

Another good choice for Top 10 Best Mail Transfer Agents (MTA) For Linux Servers is Alpine . It is a free software email client designed for Linux servers. It is highly customizable and supports Unicode and other features. The software works based on the Pine messaging system and is highly suitable for beginners and power users. The text user interface (TUI) allows users to easily adapt to the working of fast and easy to use mail transfer agents.

It comprises a rich set of shortcut keys for all navigation and operations. Also, Alpine supports various protocols, like IMAP, SMTP, NNTP, POP, and LDAP protocols. Unlike other Mail transfer agents, Alpine allows administrators to make changes to most configuration options.

Features of Alpine

  • A fast and easy to use mail transfer agent.
  • Highly customizable.
  • Blocks legitimate messaging.
  • Supports SSH login.
  • Console applications.
  • Licensed under the Apache License.
  • Allows users to make changes to configuration options.
  • It has a text user interface (TUI).
  • Supports IMAP, SMTP, NNTP, POP, and LDAP protocols.
  • It has its own editor Pico.
  • Allows sharing same address book amid various accounts.

7. OpenSMTPD

Developed by Gilles Chehade and Eric Faurot, OpenSMTPD is another popular mail transfer agent. It is a free SMTP implementation designed to allow email exchange using the SMTP protocol. Anyone under an ISC license can use or reuse the software.

It helps deliver messages to local systems or other SMTP servers. Furthermore, it also allows users to forward emails using an HTTP web server. OpenSMTPD is an easy and effective solution compatible with all Unix and Unix like operating systems, like OpenBSD, Linux, NetBSD, FreeBSD, and OSX.

Began as a part of the OpenBSD project, now the design is used by many companies as it offers high level security, ease of configuration, and other features.

Features of OpenSMTPD

  • Offers additional standard extensions.
  • Supports SMTP protocol.
  • Delivers mail to local systems or SMTP servers.
  • Supports HTTP web server.
  • Privilege escalation.
  • OpenSMTPD is highly compatible with Unix and Unix like operating systems.
  • Ease of configuration.
  • Backup and restore features.
  • Secure and reliable MTA.
  • Offers high performance.
  • Uses bounded buffer operations via strlcpy.

8. Cuttlefish

Next on the list of Top 10 Best Mail Transfer Agents (MTA) For Linux Servers is Cuttlefish. What makes Cuttlefish a top choice is its excellent web interface. Cuttlefish makes it much easier for users to monitor and use the software. It allows administrators to monitor and check IP reputation with just a click.

Cuttlefish supports SMTP protocol and helps monitor all your incoming and outgoing emails at ease. You can also keep track of all messages that reached their destination or bounced back due to the failure. Furthermore, you can view all the mail opened by the users and which links were clicked by the recipient.

It is one of the best software but does not support HTTP API, yet a top choice. It also uses postfix for routing and email delivery.

Features of Cuttlefish

  • The web interface helps in easy monitoring.
  • Supports SMTP protocol.
  • Real time analysis.
  • Supports email tracking.
  • Allows checking IP reputation.
  • A reliable and flexible mail server that ensures delivery to the destination.

9. Postal

Postal is a free, fully featured on premise mail server that aids in the quick transferring of email messages using SMTP. It supports HTTP API for easy integration with other web applications. Another feature that makes it a top choice is spam and antivirus protection.

The Postal mail server is easy to use and install open source software that allows administrators to store and provide real time analysis to all the send and receive messages. It is one of the best MTA for Linux servers to improve email tracking. For bulk email sending, the software also supports IP pools.

Users can view all the incoming and outgoing emails using graphs and stats. It allows support to multiple organizations with one install. Further, it provides Docker installation support, SMTP email delivery, live statistics, Spam and thread checking.

Features of Postal

  • Offers DNS checking and monitoring
  • IP protection.
  • Graphs and stats to view mail records.
  • Allows viewing outgoing and incoming message queue.
  • Delivery logging and auditing
  • Spam protection.
  • Real time analytics.
  • Postal Mail server is easy to install and manage.
  • Handles multiple credentials per server.
  • Docker installation support.
  • Forwards incoming email to HTTP endpoints, other SMTP servers, or other email addresses.

10. Mail-in-a-box

Last on the list of Top 10 Best Mail Transfer Agents (MTA) For Linux Servers is Mail-in-a-Box . It is is a free, open Source, self hosted and on premise Mail Server Software developed by Joshua Tauberer. The purpose to design the software was to make it easier for users and administrators to quickly turn any new cloud system into a Mail server without any technical knowledge or expertise.

Mail-in-a-Box is easy to set up, offers full control and supports to users, and allows automatic DNS configuration. Further, the software supports IMAP/SMTP, Spam filtering, Greylisting, monitoring, reporting and backup mechanisms. With the help of Mail-in-a-box, users can host mail for multiple users and domain names.

Features of Mail-in-a-Box

  • Self hosted.
  • Mail-in-a-Box is easy to set up and requires no expertise.
  • Easy administration
  • Supports Automatic DNS configuration.
  • Supports IMAP/SMTP
  • Spam filtering.
  • RESTful API.
  • HTTPS TLS support.
  • It requires no additional configuration.
  • Supports Greylisting.
  • Supports contacts and calendar synchronization.
  • Supports reporting and backup mechanisms.

Top 10 Best Mail Transfer Agents (MTA) For Linux Servers Conclusion

An email has been a great source of communication over the years. Various companies exchange essential documents and files over the network using email. There are specific email clients that ease the process.

Further, help in transferring messages from one system to the other. These email clients make use of SMTP and other protocols to help deliver your message to other email servers fast and securely.

Get full control over the email sending process using the mail transfer agents. It is software that helps transfer emails to and from between computers using SMTP protocol. Furthermore, most of these software help store all your mail and aids in monitoring and tracking the performance. Some of the above listed mail transfer agents offer real time analysis.

Check the list of top mail transfer agents for Linux servers that can help improve email tracking and performance. Each mail transfer agent has its own benefit and features that make it a part of this list. Some of them offer support to Post Office Protocol 3 (POP3) and Internet Message Access Protocol (IMAP) for receiving mails.

A few of them allow users to preview, delete and organize emails as per their convenience before sending to multiple devices using the protocols. There are several other MTAs available online, but we have shortlisted some of the best software for better performance and monitoring.

Avatar for Hitesh Jethva
Hitesh Jethva

I am a fan of open source technology and have more than 10 years of experience working with Linux and Open Source technologies. I am one of the Linux technical writers for Cloud Infrastructure Services.

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Goudounov Goudounov

You can also have a look at vSMTP.
vSMTP is a next-gen Mail Transfer Agent, that is fast, safe, and easy to use!
* It is 100% built-in Rust.
* It is modular and highly customizable.
* It has a complete filtering system using a custom scripting language based on Rhai.
vSMTP is fully open-source.
Have a nice day!
The repository:

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