The Courier Mail Server is a

mail transfer agent Within the Internet email system, a message transfer agent (MTA), mail transfer agent, or mail relay is software that transfers electronic mail messages from one computer to another using the Simple Mail Transfer Protocol. In some contexts, the a ...

(MTA) server that provides

SMTP The Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients typi ...

IMAP In computing, the Internet Message Access Protocol (IMAP) is an Internet standard protocol used by email clients to retrieve email messages from a mail server over a TCP/IP connection. IMAP is defined by . IMAP was designed with the goal of per ...

POP3 In computing, the Post Office Protocol (POP) is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a mail server. Today, POP version 3 (POP3) is the most commonly used version. Together with IMAP, i ...

SMAP was a Japanese boy band, composed of Masahiro Nakai, Takuya Kimura, Goro Inagaki, Tsuyoshi Kusanagi, and Shingo Katori. The group was created in 1988 by music producer Johnny Kitagawa, founder of Johnny & Associates, originally as a six-p ...

webmail Webmail (or web-based email) is an email service that can be accessed using a standard web browser. It contrasts with email service accessible through a specialised email client software. Additionally, many internet service providers (ISP) prov ...

, and

mailing list A mailing list is a collection of names and addresses used by an individual or an organization to send material to multiple recipients. Mailing lists are often rented or sold. If rented, the renter agrees to use the mailing list only at contra ...

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

maildir The Maildir e-mail format is a common way of storing email messages on a file system, rather than in a database. Each message is assigned a Computer file, file with a unique name, and each mail folder is a file system directory containing these fil ...

s 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 Perl is a high-level, general-purpose, interpreted, dynamic programming language. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language". Perl was developed ...

scripts. 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 The Lightweight Directory Access Protocol (LDAP ) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed Directory service, directory information services over an Internet Protocol (IP) networ ...

directory service,

Berkeley DB Berkeley DB (BDB) is an embedded database software library for key/value data, historically significant in open-source software. Berkeley DB is written in C with API bindings for many other programming languages. BDB stores arbitrary key/data ...

MySQL MySQL () is an Open-source software, open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, and "SQL", the acronym for Structured Query Language. A rel ...

PostgreSQL PostgreSQL ( ) also known as Postgres, is a free and open-source software, free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance. PostgreSQL features transaction processing, transactions ...

authentication database. Parts of Courier, such as the

maildrop Maildrop is a Mail delivery agent used by the Courier Mail Server. The maildrop Mail Delivery Agent (MDA) also includes filtering functionality. Maildrop receives mail via stdin and delivers in both Maildir and mbox formats. Features Mail ...

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 qmail is a mail transfer agent (MTA) that runs on Unix. It was written, starting December 1995, by Daniel J. Bernstein as a more secure alternative to the popular Sendmail program. Originally license-free software, qmail's source code wa ...

Exim Exim is a mail transfer agent (MTA) used on Unix-like operating systems. Exim is a free software distributed under the terms of the GNU General Public License, and it aims to be a general and flexible mailer with extensive facilities for checkin ...

, and Postfix servers that are configured to use maildirs. Courier's source compiles on most

POSIX The Portable Operating System Interface (POSIX; ) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines application programming interfaces (APIs), along with comm ...

-based operating systems based on

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

and BSD-derived kernels. It uses SMTP extensions for list management and spam filtering.

References

External links

* * /www.courier-mta.org/install.html Installing and configuring Courier-IMAPbr>Setting up a mail server
- includes Courier as the IMAP component Message transfer agents Free email server software Email server software for Linux {{Email servers

See also

References

External links