Windows Server

Windows Server (formerly known as Windows NT 3.1 and Windows 2000 Server) is a brand name for a group of server operating systems released by Microsoft. It includes all Windows operating systems that are branded "Windows Server", but not any other Microsoft product. The first Windows server edition to be released under that brand was Windows Server 2003. However, the first server edition of Windows was Windows NT 3.1 followed by Windows NT 3.5, Windows NT 4.0, and Windows 2000 Server; the latter was the first server edition to include Active Directory, DNS Server, DHCP Server, Group Policy, SQL Server, as well as many other popular features used today.

Long Term Servicing Channel (LTSC)
Windows Server operating system releases under the Long Term Servicing Channel are supported by Microsoft for 10 years, with five years of mainstream support and an additional five years of extended support. These releases also offer a complete GUI desktop experience, along with GUI less setups such as Server Core and Nano Server for releases that support them.

This channel includes the following operating systems:
 * Windows Server 2003 (April 2003)
 * Windows Server 2003 R2 (December 2005)
 * Windows Server 2008 (February 2008)
 * Windows Server 2008 R2 (October 2009)
 * Windows Server 2012 (September 2012)
 * Windows Server 2012 R2 (October 2013)
 * Windows Server 2016 (September 2016)
 * Windows Server 2019 (October 2018)
 * Windows Server 2022 (August 2021)

Semi-Annual Channel (SAC)
Windows Server operating system releases under the Semi-Annual Channel are supported by Microsoft for 18 months. Microsoft targets two releases of Windows Server per year under this channel. These releases do not offer any GUI desktop environments, and include Server Core and Nano Server.

Operating systems from this channel are available as part of subscription services, including Software Assurance, Azure Marketplace, Visual Studio subscriptions, and others.

This channel includes the following operating systems: Certain editions of Windows Server have a customized name. For example, all editions of Windows Server to this date had a Windows Storage Server edition. Starting with Windows Server 2012, Windows Storage Server was discontinued, as Microsoft consolidated the editions to Standard and Datacenter. Other examples include Windows Home Server and Windows HPC Server.
 * Windows Server, version 1709 (September 2017)
 * This version was originally available for Microsoft Software Assurance customers with an active Windows Server 2016 license.
 * Windows Server, version 1803
 * Windows Server, version 1809

Microsoft has also produced Windows Server Essentials (formerly Windows Small Business Server) and the discontinued Windows Essential Business Server, software bundles which include a somewhat restricted Windows Server operating system and some other Microsoft Server products.

Deployment
Users of Windows Server may choose to deploy either on-site or using a cloud computing service. Each provides different advantages.

By delegating the managing and upkeep of the server to a cloud computing service such as Microsoft Azure or Amazon Web Services, users get the benefit of paying monthly based on usage rather than a large fixed cost. Furthermore, infrastructure tends to be more reliable and it is easier to scale up as necessary. However, buying and running a server in-house may be a better choice in certain cases when it is more cost effective. Other use cases such as using a Windows server to manage client computers in a facility are also appropriate for running a physical server.