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.
Key Features
- 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.
Related Software
| Email Servers | |
|---|---|
| Exim | Highly configurable mail transfer agent |
| OpenSMTPD | Implementation of the server-side SMTP protocol with additional extensions |
| mox | Modern, secure, all-in-one email server |
| DBMail | Enables storing and retrieving mail messages from a database |
| WildDuck | Opinionated email server |
| Stalwart | All-in-one mail and collaboration server |
| Mailu | Self-hosted mail server stack |
| Mail-in-a-Box | Self-hosted email server solution |
| Postfix | Popular mail transfer agent |
| Maddy | Composable all-in-one mail server |
| Haraka | Modern SMTP server |
| Dovecot | Secure POP3 server that supports mbox and maildir mailboxes |
| Courier | Integrated mail/groupware server |
| Cyrus IMAP | Email, contacts and calendar server |
| Zimbra | Zimbra Collaboration Suite |
| Modoboa | Mail hosting and management platform |
| Citadel | Exchange-killer groupware server |
| chasquid | SMTP server with a focus on simplicity, security, and ease of operation |
| Sendmail | Mail transfer agent for sophisticated mail configurations |
| qmail | Written as a more secure replacement for the Sendmail program |
| dma | DragonFly Mail Agent |
| DavMail | POP/IMAP/SMTP/Caldav/Carddav/LDAP exchange gateway |
Read our verdict in the software roundup.
 Explore our comprehensive directory of recommended free and open source software. Our carefully curated collection spans every major software category.This directory is part of our ongoing series of informative articles for Linux enthusiasts. It features hundreds of detailed reviews, along with open source alternatives to proprietary solutions from major corporations such as Google, Microsoft, Apple, Adobe, IBM, Cisco, Oracle, and Autodesk. You’ll also find interesting projects to try, hardware coverage, free programming books and tutorials, and much more. Discovered a useful open source Linux program that we haven’t covered yet? Let us know by completing this form. |