Cyrus IMAP is an email, contacts and calendar server designed for environments ranging from individual servers to large multi-server installations.
Unlike mail systems where mailboxes correspond directly to users’ home directories, Cyrus maintains its own mailbox storage and databases. Users therefore do not require conventional login access to the underlying server.
Although IMAP remains central to the project, Cyrus has developed into a broader data server supporting modern mail, calendar and contact protocols.
This is free and open source software.
Key Features
- IMAP and POP3 access to email.
- JMAP support for modern mail and related data access.
- CalDAV calendar services.
- CardDAV contact services.
- WebDAV support.
- Server-side Sieve mail filtering.
- Per-user and per-mailbox quotas.
- Fine-grained access control lists.
- Shared and public mailboxes.
- Server replication for resilient installations.
- Designed for scalable multi-server deployments.
- Mailbox searching and indexing.
- Authentication integration with external services.
- Users do not need local shell accounts on the mail server.
Website: www.cyrusimap.org
Support:
Developer: Cyrus IMAP Project
License: BSD 3-Clause License (CMU variant)
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 carefully curated directory of recommended free and open source software, covering every major software category.The directory forms part of our extensive collection of articles for Linux enthusiasts. It includes hundreds of detailed reviews, together with free and open source alternatives to proprietary software from companies such as Google, Microsoft, Apple, Adobe, IBM, Cisco, Oracle, and Autodesk. LinuxLinks also covers interesting projects worth exploring, Linux-compatible hardware, free programming books and tutorials, and much more. Know a useful free and open source Linux application that we haven’t covered? Tell us about it using our submission form. |
Please read our Comment Policy before commenting.