The Courier mail server
is a mail transfer agent
(MTA) server that provides ESMTP
, and mailing list
services with individual components. It is best known for its IMAP server component.
Courier can function as an intermediate mail relay, between an internal LAN and the Internet, or perform final delivery to mailboxes. Courier uses maildirs
as its native storage format and can also deliver mail to legacy mailbox files. Configuration files are in plain text format and may include Perl
Courier can provide mail services for regular operating system accounts. Courier can also provide mail services for virtual mail accounts, managed by any of LDAP
directory service, Berkeley DB
Parts of Courier, such as the maildrop
filtering system, the webmail and IMAP server, can also be installed as independent packages which can be used with other mail servers. Courier-IMAP is a particularly popular combination with Qmail
, and Postfix
servers that are configured to use maildirs.
Courier's source compiles on most POSIX
-based operating systems based on Linux
and BSD-derived kernels. It uses SMTP extensions for list management and spam filtering.
A review of SourceForge
on February 24, 2009 indicates that Courier had been downloaded from that site over 1,000,000 times ranking 282nd on all packages with numerous
- - includes Courier as the IMAP......