Editing Microsoft Exchange Server (section)

{{short description|Calendaring and mail server}}
{{Use American English|date=January 2016}}
{{Use mdy dates|date=October 2018}}
{{Infobox software
| name = Microsoft Exchange Server
| logo = [[File:Microsoft Exchange (2019-present).svg|64px]]
| logo caption = Exchange Server 2019 logo
| developer = [[Microsoft]]
| released = {{Start date and age|1996|04|2}}<ref name="initial-release" />
| operating system = [[Windows Server]]
| platform = [[x64]]
| language = <!-- Please, do not forget your source -->
| genre = [[Collaborative software]]
| license = [[Proprietary software|Proprietary]] [[commercial software]]
}}
'''Microsoft Exchange Server''' is a [[mail server]] and [[calendaring software|calendaring]] server developed by [[Microsoft]]. It runs exclusively on [[Windows Server]] operating systems.

The first version was called Exchange Server 4.0, to position it as the successor to the related [[Microsoft Mail]] 3.5. Exchange initially used the [[X.400]] directory service but switched to [[Active Directory]] later. Until version 5.0, it came bundled with an email client called '''Microsoft Exchange Client'''. This was discontinued in favor of [[Microsoft Outlook]].

Exchange Server primarily uses a proprietary protocol called [[MAPI]] to talk to [[email client]]s, but subsequently added support for [[Post Office Protocol|POP3]], [[Internet Message Access Protocol|IMAP]], and [[Exchange ActiveSync|EAS]]. The standard [[Simple Mail Transfer Protocol|SMTP]] protocol is used to communicate to other Internet mail servers.

Exchange Server is licensed both as [[on-premises software]] and [[software as a service]] (SaaS). In the on-premises form, customers purchase [[client access license]]s (CALs); as SaaS, Microsoft charges a monthly service fee instead.