Understand Exchange 2010 licensing options

Scott Lowe helps you make sense of Exchange Server 2010's numerous licensing options. He also provides a description of the external connector license.

Microsoft isn't known for making its licensing easy to understand; in fact, many of the company's products have numerous licensing options that are often confusing. Exchange Server 2010 licensing options don't vary from this pattern. Here are the server-side and client-side licensing options that are available for the product. I'll also provide a description of the external connector.

Server-side licensing

If you're going to use on-premises Exchange, you need a server, as well as Exchange licenses for each server (physical or virtual) on which you install the Exchange software.

For quite some time, Microsoft has offered server licensing in two editions -- Standard and Enterprise -- and there used to be significant differences between the editions, but that's changed a lot with Exchange 2010; now, it's all about scale.

  • Exchange 2010 Standard edition. Supports up to a total of 5 mailbox databases per server.
  • Exchange 2010 Enterprise edition. Supports up to a total of 100 mailbox databases per server.

In previous versions of Exchange, you didn't have the full range of availability options in the Standard edition that were available in the Enterprise edition. With Exchange 2010, both editions fully support Database Availability Groups as long as you're running Exchange on the Enterprise edition of Windows Server.

Client-side licensing

Client licensing comes in Standard and Enterprise editions, but there's a catch: You can't buy just an Enterprise client access license (CAL); if you want an enterprise feature such as unified messaging, you must first buy a Standard CAL to unlock the basic functionality, and then you add on the Enterprise CAL to add the advanced features. Microsoft calls this "additive licensing." So, in essence, you buy two CALs for each user who needs enterprise-level features. It might sound unnecessary, but it's kind of nice because you can mix-and-match the licenses to suit your needs. For example, if you only have several users who need functionality provided by the Enterprise CAL (such as Unified Messaging), you just need to buy Enterprise CALs for those users. For all other users, you can stick with the Standard option and save a few bucks.

Microsoft also makes a Services add-on available that provides some additional Exchange security options.

Top of Form Feature

Bottom of Form

Standard CAL Std. + Ent. CAL (both licenses) Std. + Ent. CAL plus Services
Email Yes Yes Yes
Calendar Yes Yes Yes
Contacts Yes Yes Yes
Tasks Yes Yes Yes
Outlook Web App (cross browser) Yes Yes Yes
ActiveSync Mobile Access Yes Yes Yes
Role Based Admin. Control Yes Yes Yes
Integration of IM, SMS, and RSS Yes Yes Yes
Federated Calendar Sharing Yes Yes Yes
ActiveSync Mobile Policies Standard Advanced Advanced
Journaling Per Database Per User / Distribution List Per User / Distribution List
Voicemail with Unified Messaging No Yes Yes
Retention Policies Default Custom Custom
Integrated Archive No Yes w/Office 2010 Pro Plus Yes w/Office 2010 Pro Plus
Multi-Mailbox Search No Yes Yes
Legal Hold No Yes Yes
Information Protection & Control No Yes Yes
Top of Form

Forefront Security for Exchange

Bottom of Form

No No Yes
Forefront Online Security for Exchange No No Yes

Bottom of Form

It's important to understand that basic email functionality is not allowed with just the Enterprise CAL. If you want email, calendaring, and other typical Exchange functionality, you need to buy the Standard CAL. If you want advanced features, such as Unified Messaging, you need to buy two CALs.

Client CALs can be licensed per user or per device. If any of your users share machines (e.g., shift workers), you can save money with per-device CALs. If you have users who need to access Exchange from multiple devices, you should go with per-user CALs.

Note: A Standard or Enterprise CAL can be used with either server edition -- Standard or Enterprise. You don't need to match editions.

External connector

If you have external users (e.g., business partners, suppliers, customers, retirees, and alumni) who need to access your Exchange server, the external connector license grants access to the Exchange server by an unlimited number of these external users.


Exchange 2010 has a number of licensing options. This article is intended to help you get your bearings with regard to these options. For specific questions, please contact your Microsoft licensing reseller.

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