Courier mail server - IMAP server

 The Courier mail transfer agent (MTA) is an integrated mail/groupware
 server based on open commodity protocols, such as ESMTP, IMAP, POP3, LDAP,
 SSL, and HTTP. Courier provides ESMTP, IMAP, POP3, webmail, and mailing list
 services within a single, consistent, framework.
 .
 This package provides an IMAP server that accesses email stored in Maildirs
 format mailboxes. This server has an extremely small footprint and provides
 shared and virtual shared folders.