The UW IMAP server was the reference server implementation of the

Internet Message Access Protocol 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 ...

. It was developed at the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...

Mark Crispin Mark Reed Crispin (July 19, 1956 in Camden, New Jersey – December 28, 2012 in Poulsbo, Washington) is best known as the father of the Internet Message Access Protocol (IMAP), having invented it in 1985 during his time at the Stanford Knowle ...

and others.

History

UW-IMAP's development began c.1988. As of 2003, UW IMAP was among the three most popular

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

IMAP server packages, the other two being Cyrus IMAP and Courier IMAP. As of 2005, by which point its codebase had undergone extensive rewriting, it was among the top two, the other being Cyrus IMAP. In May 2008, the University of Washington terminated development of UW IMAP. On 4 August 2008, staff at the University of Washington who had been involved in developing UW IMAP, Pine, and Alpine, announced that they would "shift our effort from direct development into more of a consultation and coordination role to help integrate contributions from the community," in the wake of layoffs at the University of Washington's technology division. c. January - August 2009, the maintainers of

Debian Debian (), also known as Debian GNU/Linux, is a Linux distribution composed of free and open-source software, developed by the community-supported Debian Project, which was established by Ian Murdock on August 16, 1993. The first version of D ...

GNU/Linux, a major downstream distributor of UW IMAP, began to retire their UW IMAP packages. In September 2009, Mark Crispin, the principal author of UW IMAP, announced a fork called Panda IMAP. Crispin passed away in late 2012. At least one UW IMAP enthusiast maintains a public

source code repository In version control systems, a repository is a data structure that stores metadata for a set of files or directory structure. Depending on whether the version control system in use is distributed, like Git or Mercurial, or centralized, like Subversi ...

containing the UW IMAP and Panda IMAP commit history from the start of the project until Crispin's final release.

Praise and criticism

For much of the 2000s, UW IMAP was considered to be a good choice due to its ready availability, its inclusion in all major Linux distributions, its support for both POP and IMAP, and its ease of installation. It also received praise for its ease of administration and for its compatibility with longstanding mailbox formats, and for and its small size and simplicity. Unlike later IMAP servers, UW IMAP coupled IMAP user accounts to user accounts on the server's underlying operating system. This feature, together with UW IMAP's default use of monolithic mailbox files, was intended to ensure compatibility with legacy operating systems and email management practices, but drew criticism from some commentators. In particular, Sam Varshavchik, developer of the competing Courier IMAP server, suggested that Crispin's decision not to add support for maildir (a popular non-monolithic mailbox format) to UW IMAP may have stemmed from lingering resentment over an earlier disagreement that Crispin had had with maildir's designer, Daniel J. Bernstein. Crispin's insistence upon retaining UW IMAP's support for flat files as mail stores was criticised, by the maintainers of the competing

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IMAP server, for causing otherwise unnecessary complexity in the IMAP protocol. Additionally, Varshavchik noted that despite Crispin's insistence that other IMAP servers comply with the IMAP specifications, the UW IMAP server and its IMAP client counterpart, Pine, used a private IMAP extension that was not documented in that specification. UW IMAP was also criticised for its susceptibility to

buffer overflow In information security and programming, a buffer overflow, or buffer overrun, is an anomaly whereby a program, while writing data to a buffer, overruns the buffer's boundary and overwrites adjacent memory locations. Buffers are areas of memory ...

s and for its lack of

privilege separation In computer programming and computer security, privilege separation is one software-based technique for implementing the principle of least privilege. With privilege separation, a program is divided into parts which are limited to the specific pri ...

relative to its competitors Cyrus and Courier, As of 2007, computer programs existed that were capable of exploiting security vulnerabilities in un-patched or improperly-configured UW IMAP installations. and for its unreliable SSL support.

Components and features

UW IMAP was designed to be compatible with existing legacy mail stores and systems, and to be "plug-and-play" installable without requiring any site-specific configuration. UW IMAP uses the c-client mail engine that is also used by the

Alpine Alpine may refer to any mountainous region. It may also refer to: Places Europe * Alps, a European mountain range ** Alpine states, which overlap with the European range Australia * Alpine, New South Wales, a Northern Village * Alpine National Pa ...

and

Pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

e-mail clients. c-client supports multiple mail store formats including

Usenet Usenet () is a worldwide distributed discussion system available on computers. It was developed from the general-purpose Unix-to-Unix Copy (UUCP) dial-up network architecture. Tom Truscott and Jim Ellis conceived the idea in 1979, and it was ...

news spools, MIX,

mbox Mbox is a generic term for a family of related file formats used for holding collections of email messages. It was first implemented in Research Unix, Fifth Edition Unix. All messages in an mbox mailbox are concatenated and stored as plain text ...

, , , , , , MMDF, and . c-client also includes support for

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. POP version 3 (POP3) is the version in common use, and along with IMAP the most common p ...

NNTP The Network News Transfer Protocol (NNTP) is an application protocol used for transporting Usenet news articles (''netnews'') between news servers, and for reading/posting articles by the end user client applications. Brian Kantor of the Univers ...

, and

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 typical ...

Internet protocols. Also bundled with UW IMAP are POP2 and

servers, the utility program, and the and

mail delivery agent A message delivery agent (MDA), or mail delivery agent, is a computer software component that is responsible for the delivery of e-mail messages to a local recipient's mailbox., ''Internet Mail Architecture'', D. Crocker (July 2009) It is also call ...

s. As of 2005, UW IMAP's codebase consisted of 135,000

lines of code Source lines of code (SLOC), also known as lines of code (LOC), is a software metric used to measure the size of a computer program by counting the number of lines in the text of the program's source code. SLOC is typically used to predict the am ...

, of which the IMAP server itself comprised 4,000 lines and c-client comprised the rest.

Extensibility and maildir support

UW IMAP does not officially support the maildir format. However, UW IMAP can be patched to support other formats, such as maildir. Gluelogic offers a patch to support maildirs in Pine. The patched Pine instance can then be used to compile UW IMAP with nominal maildir support. However, this yields a buggy server that will not correctly distinguish between Unseen and Recent messages. A patch is available for Alpine that can be used similarly, but with fewer drawbacks.

External links

Home Page of UW IMAPaccessed 28 October 2019

UW IMAP mailing list

References

Bibliography

* * * * * * * * * * * * * * * * {{DEFAULTSORT:Uw Imap Free email software Unix Internet software Portable software Message transfer agents