The Courier IMAP server - Feature
          Summary
         
       
     
    
      
        - Extremely small footprint. On x86, the
        Courier IMAP server's main
        daemon is a fraction of the size of the UW-IMAP server, and
        has a greatly reduced memory footprint.
- Uses the Courier Authentication Library for
        authenticating mail accounts.
- Ability to restrict the maximum number
        of IMAP logins, and the
        maximum number of logins from the same IP address. This
        will prevent denial-of-service attacks where the attacker
        attempts to overload the server with multiple login
        connections.
- Shared folders. With additional
        server-side setup, folders can be shared between groups of
        accounts.
- IMAP over SSL. If OpenSSL or GnuTLS is installed, the
        Courier IMAP server will,
        optionally, accept IMAP
        connections over SSL.
        The IMAP STARTTLS
        extension is also implemented.
- Authentication using SSL certificates.
- IPv6 support, if available.
- IMAP extensions that implement
        server-side sorting. This can be optionally disabled in
        environments that have limited resources.
- The Courier IMAP server implements many
        popular IMAP protocol
        extensions that provide value-added functionality with most
        popular IMAP
        clients.
- Sorting and searching in non-English
        character sets. Download the source code to obtain a list
        of currently supported character sets.
- A compatible POP3 server is also included in the
        Courier IMAP server
        package, that uses the same authentication modules. The
        POP3 server can only
        access the INBOX, and cannot access any folders.
- An experimental mail access protocol,
        SMAP.
- IMAP/POP3 proxying. It is possible to
        distribute all mailboxes between multiple servers. A
        separate server (or a pool of servers) accepts all
        IMAP/POP3 connections, then connects to the
        right server based on the mailbox the connecting client is
        logging into.