Exim is an open source mail transfer agent (MTA), which is software responsible for receiving, routing, and delivering e-mail messages (this type of program is sometimes referred to as an Internet mailer, or a mail server program).
Exim is highly configurable, and has features that are lacking in other MTAs. It has always had substantial facilities for mail policy controls, providing facilities for the administrator to control who may send or relay mail through the system. In version 4.x this has matured to an Access Control List based system allowing very detailed and flexible controls.
Exim somewhat resembles Smail 3, but it has diverged and now surpasses it in user friendliness and flexibility.
Features include:
- RFC 2821 SMTP and RFC 2033 LMTP email message transport.
- Incoming (as SMTP server):
- SMTP over TCP/IP (Exim daemon or inetd).
- SMTP over the standard input and output (the -bs option).
- Batched SMTP on the standard input (the -bS option).
- Supports RFC 5068 Message Submission, as an SMTP server with (for example, encrypted and authenticated connections on port 587).
- Outgoing email (as SMTP or LMTP client):
- SMTP over TCP/IP (the smtp transport).
- LMTP over TCP/IP (the smtp transport with the protocol option set to “lmtp”).
- LMTP over a pipe to a process running in the local host (the lmtp transport).
- Batched SMTP to a file or pipe (the appendfile and pipetransports with the use_bsmtp option set).
- Configuration
- Access Control Lists – flexible policy controls.
- Content scanning, including easy integration with and other spam and virus scanners like SpamAssassin and ClamAV.
- Encrypted SMTP connections using TLS/SSL.
- Authentication with a variety of front end and back end methods, including PLAIN, LOGIN, sasl, dovecot, spa, cram_md5.
- Rewrite – rewrite envelope and/or header addresses using regular expressions.
- Routing controls – use routers to redirect, quarantine, or deliver messages.
- Transports – use transports to deliver messages by smtp, lmtp, or to files, directories, or other programs.
- Flexible retry rules for temporary delivery problems.
Website: www.exim.org
Support: Documentation
Developer: University of Cambridge
License: GNU General Public License v2.0
Exim is written in C. Learn C with our recommended free books and free tutorials.
Return to Email | Return to Email Servers
| Popular series | |
|---|---|
 | The largest compilation of the best free and open source software in the universe. Each article is supplied with a legendary ratings chart helping you to make informed decisions. |
 | Hundreds of in-depth reviews offering our unbiased and expert opinion on software. We offer helpful and impartial information. |
 | The Big List of Active Linux Distros is a large compilation of actively developed Linux distributions. |
 | Replace proprietary software with open source alternatives: Google, Microsoft, Apple, Adobe, IBM, Autodesk, Oracle, Atlassian, Corel, Cisco, Intuit, and SAS. |
 | Awesome Free Linux Games Tools showcases a series of tools that making gaming on Linux a more pleasurable experience. This is a new series. |
 | Machine Learning explores practical applications of machine learning and deep learning from a Linux perspective. We've written reviews of more than 40 self-hosted apps. All are free and open source. |
 | New to Linux? Read our Linux for Starters series. We start right at the basics and teach you everything you need to know to get started with Linux. |
 | Alternatives to popular CLI tools showcases essential tools that are modern replacements for core Linux utilities. |
 | Essential Linux system tools focuses on small, indispensable utilities, useful for system administrators as well as regular users. |
 | Linux utilities to maximise your productivity. Small, indispensable tools, useful for anyone running a Linux machine. |
 | Surveys popular streaming services from a Linux perspective: Amazon Music Unlimited, Myuzi, Spotify, Deezer, Tidal. |
 | Saving Money with Linux looks at how you can reduce your energy bills running Linux. |
 | Home computers became commonplace in the 1980s. Emulate home computers including the Commodore 64, Amiga, Atari ST, ZX81, Amstrad CPC, and ZX Spectrum. |
 | Now and Then examines how promising open source software fared over the years. It can be a bumpy ride. |
 | Linux at Home looks at a range of home activities where Linux can play its part, making the most of our time at home, keeping active and engaged. |
 | Linux Candy reveals the lighter side of Linux. Have some fun and escape from the daily drudgery. |
 | Getting Started with Docker helps you master Docker, a set of platform as a service products that delivers software in packages called containers. |
 | Best Free Android Apps. We showcase free Android apps that are definitely worth downloading. There's a strict eligibility criteria for inclusion in this series. |
 | These best free books accelerate your learning of every programming language. Learn a new language today! |
 | These free tutorials offer the perfect tonic to our free programming books series. |
 | Linux Around The World showcases usergroups that are relevant to Linux enthusiasts. Great ways to meet up with fellow enthusiasts. |
 | Stars and Stripes is an occasional series looking at the impact of Linux in the USA. |