Cyrus IMAP is an email, contacts and calendar server.
The Cyrus IMAP server differs from other IMAP server implementations in that it is generally intended to be run on “sealed” servers, where normal users are not permitted to log in. The mailbox database is stored in parts of the filesystem that are private to the Cyrus IMAP system. All user access to mail is through the IMAP, NNTP, or POP3 protocols.
The private mailbox database design gives the server large advantages in efficiency, scalability, and administrability. Multiple concurrent read/write connections to the same mailbox are permitted. The server supports access control lists on mailboxes and storage quotas on mailbox hierarchies.
Cyrus has been under active development since the year 1993 when the project was launched at Carnegie Mellon University. It’s used in production systems around the world, at universities and in private enterprise.
Features include:
- Speed.
- Security.
- Efficiency.
- Search.
- CardDAV and CalDAV support.
- Robust data storage.
- Replication.
- Scalable for large installations.
- Flexible filtering support through Sieve.
- Supports antivirus and antispam toolkits.
- Handles deliverability: SPF, DKIM, DMARC.
- Extensive authentication options, through Cyrus SASL.
- JMAP support.
- Long list of supported standards.
Website: www.cyrusimap.org
Support: GitHub Code Repository
Developer: Carnegie Mellon University
License: BSD
Cyrus IMAP is written in C. Learn C with our recommended free books and free tutorials.
| 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. |