courier-imap | Courier Mail Server - IMAP server | Mehr ...
The Courier IMAP server provides access to email stored in Maildirs. This server has an extremely small footprint, provides shared and virtual shared folders.
courier-imap-ssl | Courier Mail Server - IMAP over SSL | Mehr ...
IMAP over SSL is handled by the regular IMAP daemon from courier-imap in conjunction with the SSL/TLS wrapper supplied by courier-ssl.