Guide to Exchange Server Editions and Licensing

Exchange Server provides a collaboration environment that delivers secure messaging capabilities to recipients inside and outside an organization. Besides a powerful email server, it supports group scheduling capabilities, discussion groups, team folders, mobile and web access, and a host of other features.

The purpose of this guide is to help you find the Exchange Server edition and licenses appropriate to your organization's needs.

* Standard and Enterprise Editions
* Licensing
* Upgrading and Downgrading
* Exchange Server Products Available Through CTX
Standard and Enterprise Editions

Exchange Server is offered in both standard and enterprise editions.

In the 2010 version, the only significant difference between the standard and enterprise products is the number of mailbox databases each edition allows. The standard edition allows up to 5 mailbox databases, while the enterprise edition allows up to 100. Thus, larger organizations should request the enterprise edition.

Other product functionality depends on whether an organization requests enterprise client access licenses (CALs) in addition to standard CALs. Both standard and enterprise CALs can be used with either server edition, but the enterprise CALs can be used only in conjunction with standard CALs to access certain Exchange Server features. For more information, see the Licensing section below.

Both editions of Exchange Server 2010 require x64 hardware (Intel EM64T or AMD64), which makes more efficient use of memory and storage than 32-bit hardware. If your server computer does not support x64 software, a downgrade to Exchange Server 2003 is available through Microsoft’s Volume Licensing Service Center. For more information, see the Upgrading and Downgrading section below.

Below are some of the major licensing requirements for Exchange Server:

* For each server software license you assign, you may run, at any one time, one instance of the server software in one physical or virtual operating system environment on the licensed server.
* You may run or otherwise use any number of instances of the Exchange Management Tools software in physical or virtual operating system environments on any number of devices. You may use those instances only with the server software. Use of any instance with the server software may be indirect, through other additional software, or direct.

Exchange Server is a server application, not a server operating system. Thus, it must be used along with a server operating system. For each instance of Exchange Server 2010, you must also have a Windows Server 2008 Standard, Enterprise, or Datacenter license. The Mailbox Resiliency feature in Exchange Server 2010 requires either the Enterprise or Datacenter edition of Windows Server 2008.

Client Access Licenses (CALs)

An Exchange Server device or user CAL is required for each device or user accessing or using the server software. However, you do not need CALs for:

* Up to two devices or users to access the server software only to administer those instances
* Any user or device that accesses your instances of the server software without being directly or indirectly authenticated by Active Directory

For both the standard and enterprise editions of Exchange Server, the standard device or user CALs authorize one user or device to access Exchange Server.

Enterprise CALs are also available for use with both versions of Exchange Server. Enterprise CALs can be used only in conjunction with standard CALs to access certain Exchange Server features. These features include integrated archiving, multimailbox search and legal hold, and unified messaging features. For a complete list, see the Exchange Server 2010 Licensing page.

Enterprise CALs do not need to be requested for users or devices that do not need to access these additional features.

Additionally, a Windows Server 2008 CAL is required for each Exchange Server 2010 user or device CAL in all scenarios. A Windows 2008 Rights Management Server (RMS) CAL is required for each Exchange Server 2010 user or device that will be making use of the Information Rights Management (IRM) features.

Microsoft offers both standard and enterprise user and device CALs for Exchange Server through TechSoup.

Upgrading and Downgrading


For help in upgrading from Exchange Server 2007 to Exchange Server 2010, see this upgrade planning guide from Microsoft.

You can use Software Assurance to upgrade Exchange Server and associated licenses to any version released during the two years your Software Assurance is in effect. The actual upgrade does not have to take place within those two years: you can upgrade at any time in the future, as long as Microsoft still makes the new version available to users. You cannot, however, upgrade to versions that Microsoft releases after your Software Assurance expires.

CALs obtained through CTX will work with the new version since they have their own Software Assurance.


You can downgrade Exchange Server to any version Microsoft continues to make available at its Volume Licensing Service Center website on your organization's Licensed Downloads page. Downgrading does not depend on Software Assurance; it is a benefit of Volume Licensing.

CALs obtained through CTX will work with the downgraded version.

Exchange Server Products Available Through CTX

The Exchange Server donations available through CTX are listed on the Exchange Server catalogue page.


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