Courier

Courier is a completely free, cross-platform and open source mail transfer agent (MTA), an integrated mail and groupware server based on open protocols, such as IMAP (Internet Message Access Protocol), POP3 (Post Office Protocol 3), SSL (Secure Sockets Layer), LDAP (Lightweight Directory Access Protocol), ESMTP, and HTTP.

Provides webmail and mailing list services

It is a mature and powerful software that provides webmail and mailing list services within a single and consistent framework, using the ESMTP (Extended SMTP), IMAP and POP3 protocols.

The best thing about Courier is that its mail filtering engine, the IMAP server, and the webmail server are available as separate packages, and can be easily installed and integrated with other mail server applications.

Getting started with Courier

Installing the Courier software on a GNU/Linux operating system is quite easy, as all you have to do is to download the latest release from Softoware, saving the archive on your Home directory. Unpack the archive, open a Terminal app, and move to the location where you’ve extracted the archive file (e.g. cd /home/softoware/courier-0.74.1).

Then, run the ‘./configure && make’ command to configure and compile the program. After a successful compilation process, run the ‘sudo make install’ command to install Courier system wide.

During the installation, you will be ascked to create directories for the web-based administration tool, as well as to create a SSL certificate. Several configuration files are available in the /etc/courier folder.

Under the hood

Taking a quick look under the hood of the Courier project, we can notice that the C++, C and Perl programming langauges have been used to write its source code. Courier is compatible with both 32 and 64-bit computer platforms, it presents itself as a non-interactive daemon, and can be deployed on any GNU/Linux or BSD machine.

What is new in this release:

• Minor security fixes.

What is new in version 0.75.0 Build 20160306:

• Minor security fixes.

What is new in version 0.75.0 Build 20151220:

• Minor security fixes.

What is new in version 0.75.0:

• Minor security fixes.

What is new in version 0.74.2:

• Minor security fixes.

What is new in version 0.74.1:

• Minor security fixes.

What is new in version 0.68.1:

• rfc2045mkboundary.c was broken in 0.68.1

What is new in version 0.66.1:

• Fix memory corruption.

What is new in version 0.64.2:

• courier/module.local/local.c (rw_local_filter): Fix crash if a local mail filter produces more than bufsiz-1 bytes.
• imapd.c (main): Dummy FAM/Gamin initialization, report an error during login,upon a failure.
• imap/imapd.c (imapenhancedidle): Make FAM error more meaningful.
• pop3dserver.c (main): "disableinsecurepop3" account option disables non-SSL logins.imapd.c (chkdisabled): "disableinsecureimap" account option disables non-SSL logins.

What is new in version 0.62.0:

• Incorrect reference to POP3_STLS in po3pdserver.c - should be POP3_TLS.
• Record authentication ID of messages in newmsg syslog entries, of messages submitted using authenticated SMTP. Note that this changes the format of
• "newmsg" syslog entries.
• Do not log socket write errors after receiving the SMTP QUIT command.
• Reduces noice - a lot of SMTP clients don't bother waiting for a response to
• QUIT.

What is new in version 0.61.2:

• This release includes fixes for several platform-specific problems that may occur when forwarding messages and when Courier is compiled against the GnuTLS library.

What is new in version 0.61.1:

• This release fixes several problems in the webmail server with handling of misformatted HTML mail.