SquirrelMail is a project that aims to provide both a web-based email client and a

proxy server In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource. Instead of connecting directly to a server that can fulfill a requ ...

for the

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 pe ...

protocol. The latest stable version 1.4.23-svn is tested with PHP up to version 8.1 and replaces version 1.4.22 which can only run on PHP version 5.0-5.4. The svn part in the version name points out that bugfixes and minor improvements are no longer published as new versions, but instead are maintained within

Apache Subversion Apache Subversion (often abbreviated SVN, after its command name ''svn'') is a software versioning and revision control system distributed as open source under the Apache License. Software developers use Subversion to maintain current and hist ...

version control system.

History

The webmail portion of the project was started by Nathan and Luke Ehresman in 1999 and is written in

PHP PHP is a General-purpose programming language, general-purpose scripting language geared toward web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1993 and released in 1995. The PHP reference implementati ...

. SquirrelMail can be employed in conjunction with a LAMP "stack", and any other operating systems that support PHP are supported as well. The web server needs access to the IMAP server hosting the email and to an

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 typic ...

server to be able to send mails. SquirrelMail webmail outputs valid

HTML The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScri ...

4.0 for its presentation, making it compatible with a majority of current

web browser A web browser is application software for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on ...

s. SquirrelMail webmail uses a plugin architecture to accommodate additional features around the core application, and over 200 plugins are available on the SquirrelMail website. The SquirrelMail IMAP proxy server product was created in 2002 by Dave McMurtrie while at the

University of Pittsburgh The University of Pittsburgh (Pitt) is a public state-related research university in Pittsburgh, Pennsylvania. The university is composed of 17 undergraduate and graduate schools and colleges at its urban Pittsburgh campus, home to the univers ...

(where it was named "up-imapproxy", although it has become more commonly known as "imapproxy") and adopted by the SquirrelMail team in 2010. It is written in C and is primarily made to provide stateful connections for stateless webmail client software to an IMAP server, thus avoiding new IMAP logins for every client action and in some cases significantly improving webmail performance. Both SquirrelMail products are

free and open-source software Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source ...

subject to the terms of the

GNU General Public License The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end user In product development, an end user (sometimes end-user) is a person who ultimately uses or is intended to ulti ...

version 2 or any later version. SquirrelMail webmail was included in the repositories of many major

Linux distribution A Linux distribution (often abbreviated as distro) is an operating system made from a software collection that includes the Linux kernel and, often, a package management system. Linux users usually obtain their operating system by downloading on ...

s and is independently downloaded by thousands of people every month.

Platforms

SquirrelMail webmail is available for any platform supporting PHP. Most commonly used platforms include

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which i ...

FreeBSD FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ...

macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac (computer), Mac computers. Within the market of ...

and the server variants of Microsoft Windows. SquirrelMail IMAP Proxy compiles on most flavors of

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

, and can generally be used on the same platforms that the webmail product can with the exception of Microsoft Windows, unless used in a

Cygwin Cygwin ( ) is a POSIX-compatible programming and runtime environment that runs natively on Microsoft Windows. Under Cygwin, source code designed for Unix-like operating systems may be compiled with minimal modification and executed. The Cygwin i ...

or similar environment. Apple shipped SquirrelMail as their supported web mail solution in

Mac OS X Server macOS Server, formerly Mac OS X Server and OS X Server, is a discontinued series of Unix-like server operating systems developed by Apple Inc., based on macOS and later add-on software packages for the latter. macOS Server added serve ...

Plugins

The SquirrelMail webmail client itself is a complete webmail system, but extra features are available in the form of

plugins Plug-in, plug in or plugin may refer to: * Plug-in (computing) is a software component that adds a specific feature to an existing computer program. ** Audio plug-in, adds audio signal processing features ** Photoshop plugin, a piece of software t ...

. There are over 200 third-party plugins available for download from the SquirrelMail website and SquirrelMail ships with several "standard" or "core" plugins.

Internationalization

SquirrelMail webmail has been translated into over 50 languages including Arabic, Chinese, French, German, and Spanish.

Notable installations

SquirrelMail has been implemented as the official email system of the Prime Minister's Office of the Republic of India for its security advantages over Microsoft's

Outlook Express Outlook Express, formerly known as Microsoft Internet Mail and News, is a discontinued email and news client included with Internet Explorer versions 3.0 through to 6.0. As such, it was bundled with several versions of Microsoft Windows, from ...

. In 2004

HEC Montréal HEC Montréal (french: École des hautes études commerciales de Montréal) is a public Canadian business school located in Montreal, Quebec, Canada. Founded in 1907, HEC Montréal is the graduate business school of the Université de Montréa ...

business school deployed SquirrelMail as part of a comprehensive webmail solution, to support thousands of users.

References

External links

* {{E-mail clients Email clients Proxy server software for Linux Free email software Free software programmed in PHP Free software webmail