Editing Cyrus IMAP server

{{Short description|Email server software}}
{{Infobox software
| name                   = Cyrus IMAP server
| logo                   = 
| screenshot             = 
| caption                = 
| developer              = [[Carnegie Mellon University]], [[Fastmail]]
| latest release version = {{wikidata|property|edit|reference|P348}}
| latest release date    = {{start date and age|{{wikidata|qualifier|preferred|single|Q899855|P348|P548=Q2804309|P577}}}}
| programming language   = [[C (programming language)|C]]
| operating system       = 
| genre                  = [[Mail delivery agent]]
| license                = [[BSD licenses|BSD]]
| website                = {{url|//www.cyrusimap.org/}}
}}

The '''Cyrus IMAP server''' is [[electronic mail]] [[Server (computing)|server]] software developed by [[Carnegie Mellon University]]. It differs from other [[Internet Message Access Protocol]] (IMAP) server implementations in that it is generally intended to be run on [[sealed server]]s, where normal users cannot log in.

==Overview==
The mail spool uses a filesystem layout and format similar to the [[Maildir]] format used by other popular [[email]] servers such as [[qmail]], [[Courier Mail Server|Courier]], [[Dovecot (software)|Dovecot]], etc. Users can access mail through the [[JSON Meta Application Protocol|JMAP]], [[IMAP]]/IMAP-S, [[POP3]]/POP3-S or [[Kerberized Post Office Protocol|KPOP]] protocols.

The Cyrus IMAP server supports server-side mail filtering through the implementation of a mail filtering language called [[Sieve (mail filtering language)|Sieve]].

The private mailbox database design gives the server considerable advantages in [[Algorithmic efficiency|efficiency]], [[scalability]], and [[system administrator|administratability]]. Multiple concurrent read/write connections to the same mailbox are permitted. The server supports access control lists on mailboxes and storage quotas on mailbox hierarchies.

As of version 2.4.17, there is support for [[CalDAV]] and [[CardDAV]] to provide an integrated calendaring and email solution, and also support for viewing email via an [[News aggregator|RSS reader]].

In terms of user management, it has a simple implementation of [[Simple Authentication and Security Layer|SASL]] which is specified in the Internet Standard RFC 2222.<ref>{{Cite book |last1=Heinlein |first1=Peer |url=https://books.google.com/books?id=YUUSdUtay1QC&q=cyrus+imap+server |title=The Book of IMAP: Building a Mail Server with Courier and Cyrus |last2=Hartleben |first2=Peer |date=2008 |publisher=No Starch Press |isbn=978-1-59327-177-0 |language=en}}</ref>

== History ==
Prior to 1994, [[Carnegie Mellon University]]'s email was based on the locally developed and non-standard ''Andrew Messaging System'' (AMS) - written in the early 1980s as part of the [[Andrew Project]]. This was very advanced for its day, but had major scalability issues and Carnegie Mellon wanted to move to a standards-compliant mail system that met or exceeded the feature set of AMS.

In 1994 the Computing Services Division at Carnegie Mellon addressed these goals by starting the Cyrus Project. In 1998, Carnegie Mellon placed all of its incoming [[freshman|freshmen]] (the class of 2002) on the Cyrus server for the first time and in December 2001, [[bulletin board system|board]] access (which had been mirrored from AMS to Cyrus), was cut over to Cyrus completely. AMS was finally phased out in May 2002.

The Computing Services Division later developed [http://www.cyrusimap.org/imap/reference/admin/murder/murder.html#murder Cyrus "Murder"] clustering,{{efn|The term "murder" is borrowed from the commonly-used [[collective noun]] for crows.<ref>{{cite web|url=http://www.cyrusimap.org/imap/reference/admin/murder/murder-concepts.html#def-murder|title=Cyrus Murder - Concepts|access-date=28 May 2017|at=Appendix C}}</ref>}} and after several revisions deployed it within Carnegie Mellon in the summer of 2002.

Several members of the Cyrus development team at Carnegie Mellon went on to become leaders in the development of large-scale electronic mail infrastructure elsewhere: John Gardiner Myers was Chief Architect of Host Mail Infrastructure at [[AOL|America Online]];<ref>{{cite web|url=https://www.linkedin.com/in/john-gardiner-myers-5a630130/|title=John Gardiner Myers|access-date=17 February 2018}}</ref> and Rob Siemborski worked on [[Gmail]] infrastructure at Google.<ref>{{cite journal|url=https://tools.ietf.org/html/rfc4954|title=RFC 4954|year=2007 |doi=10.17487/RFC4954 |access-date=17 February 2018|editor-last1=Siemborski |editor-last2=Melnikov |editor-first1=R. |editor-first2=A. |last1=Siemborski |first1=R. |last2=Melnikov |first2=A. |url-access=subscription }}</ref>

In the fall of 2016 Carnegie Mellon announced the retirement of Cyrus IMAP as their electronic mail storage service, with Cyrus users required to choose between on-campus Microsoft Exchange and Google "G Suite" off-campus mail.<ref>{{cite web|url=https://www.cmu.edu/computing/services/comm-collab/email-calendar/cyrus/decommission.html|title=Cyrus Retirement|access-date=17 February 2018|archive-date=18 February 2018|archive-url=https://web.archive.org/web/20180218091058/https://www.cmu.edu/computing/services/comm-collab/email-calendar/cyrus/decommission.html|url-status=dead}}</ref>

Cyrus is still being actively developed. Carnegie Mellon University remains active in development, and also provides the infrastructure on which cyrusimap.org runs.<ref name=who>{{cite web |title=Who Is Cyrus |url=https://www.cyrusimap.org/overview/who_is_cyrus.html |access-date=22 December 2018}}</ref> Staff at [[Fastmail]] contribute much of the recent work, as they depend upon it as part of their commercial service.<ref>{{cite web |title=Why we contribute to Cyrus IMAP |url=https://fastmail.blog/2016/12/12/why-we-contribute/ |access-date=22 December 2018 |archive-date=22 December 2018 |archive-url=https://web.archive.org/web/20181222082259/https://fastmail.blog/2016/12/12/why-we-contribute/ |url-status=dead }}</ref><ref name=who/><ref>{{cite web|url=https://blog.fastmail.com/2016/12/22/cyrus-development-and-release-plans/|title=Cyrus development and release plans|access-date=17 February 2018}}</ref>

== See also ==
* [[Comparison of mail servers]]
* [[Comparison of CalDAV and CardDAV implementations]]
* [[UW IMAP]]

==References==
{{Reflist}}
{{Reflist|group=lower-alpha}}

===Bibliography===
{{refbegin}}
* {{cite journal |title=Paranoid penguin: secure mail with LDAP and IMAP, Part I |first=Mick |last=Bauer |journal=Linux Journal |volume=2003 |issue=115, November 2003 |page=12 |url=https://dl.acm.org/citation.cfm?id=945917 |via=[[Association for Computing Machinery|ACM]] |year=2003}}
* {{cite book |first1=Tony |last1=Bautts |first2=Terry |last2=Dawson |first3=Gregor N. |last3=Purdy |title=Linux network administrator's guide |year=2005 |publisher=[[O'Reilly Media]] |url=https://books.google.com/books?id=YAhRAAAAMAAJ&q=%22uw+imap%22|isbn=9780596005481 }}
* {{cite book |title=Sendmail Performance Tuning |first=Nick |last=Christenson |publisher=Addison-Wesley Professional |year=2003 |url=https://books.google.com/books?id=AKouSFRckHoC&q=(%22reference+implementation%22+OR+%22reference+implementations%22)+%22uw+imap%22&pg=PA110|isbn=9780321115706 }}
* {{cite book |title=E-Mail Virus Protection Handbook: Protect Your E-mail from Trojan Horses, Viruses, and Mobile Code Attacks |editor-last=Glennon |editor-first=Katharine |year=2000 |publisher=[[Elsevier]] |url=https://books.google.com/books?id=oCjjlfAChIUC&q=%22uw+imap%22&pg=PA384|isbn=9780080477534 }}
* {{cite conference |title=Toward an Automated Vulnerability Comparison of Open Source IMAP Servers |first=Chaos |last=Golubitsky |conference=19th Large Installation System Administration Conference (LISA ’05) |year=2005 |url=https://www.usenix.org/event/lisa05/tech/golubitsky/golubitsky.pdf |publisher=[[USENIX]]}}
* {{cite book |title=Managing IMAP |first1=Dianna |last1=Mullet |first2=Kevin |last2=Mullet |year=2000 |publisher=[[O'Reilly Media]] |url=https://books.google.com/books?id=ZljG1e7zHCkC&q=%22uw+imap%22&pg=PA209|isbn=9780596000127 }}
* {{cite book |title=Linux Power Tools |first=Roderick W. |last=Smith |url=https://books.google.com/books?id=zY0t0TN-OJUC&q=%22uw+imap%22 |publisher=Wiley |year=2003|isbn=9780782142266 }}
* {{cite book |title=LPIC-2 Linux Professional Institute Certification Study Guide: Exams 201 and 202 |first=Roderick W. |last=Smith |year=2011 |publisher=[[John Wiley & Sons]] |url=https://books.google.com/books?id=WzNljmfNNUIC&q=cyrus&pg=PT382|isbn=9781118100448 }}
{{refend}}

==External links==
* {{official website|//www.cyrusimap.org/}}

{{Email servers}}

[[Category:Message transfer agents]]
[[Category:Free email server software]]
[[Category:Email server software for Linux]]
[[Category:Carnegie Mellon University software]]