Cyrus IMAP Server 2.1.18

The Cyrus IMAP server is generally intended to be run on sealed systems, where normal users are not permitted to log in.

Electronic mail is a major infrastructure service of almost all organizations. At Carnegie Mellon the use of electronic mail has overshadowed the use of all other distributed services since the early 1990s. It is a core part of the business process of most departments. The universal availability of the Andrew Mail and Bulletin Board System (AMS) has helped a great deal to create this situation. Departments without AMS have run their own mail systems and see heavy use, as well. With the end of the lifetime of the AMS in sight, Project Cyrus began to build a new campus mail system.

The Cyrus Electronic Mail Project is continuing to build a highly scalable enterprise mail system designed for use in a small to large enterprise environments using standards based technologies. The Cyrus technologies will scale from independent use in small departments to a system centrally managed in a large enterprise.

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This document gives an overview of the Cyrus IMAP server. The Cyrus IMAP (Internet Message Access Protocol) server provides access to personal mail and system-wide bulletin boards through the IMAP protocol. The Cyrus IMAP server is a scalable enterprise mail system designed for use from small to large enterprise environments using standards-based technologies.

A full Cyrus IMAP implementation allows a seamless mail and bulletin board environment to be set up across multiple servers. It differs from other IMAP server implementations in that it is run on "sealed" servers, where users are not normally 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 software that is using the IMAP, POP3, or KPOP protocols.

The private mailbox database design gives the server large advantages in efficiency, scalability, and administratability. 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.