Datasheet

18
Chapter 1

Designing and Planning Messaging Services
As a protective feature, Dcpromo, which is the command to promote a
Windows 2000 or 2003 member server to a domain controller, cannot be
run anymore once you have installed Exchange Server 2007 on a Windows
2003 member server. After Exchange Server 2007 is installed, changing
the role from a member server to a domain controller or vice versa is not
a Microsoft-supported scenario.
Exchange Server 2007 Roles
In order to manage Exchange Server 2007 in a more natural way, server roles were imple-
mented. These roles enable administrators to easily choose which features should be
installed on an Exchange server. They provide the following advantages over the model
used in previous Exchange versions:

They reduce attack surface, as only required roles are installed.

They allow you to install the servers for their intended role only.

They provide more possibilities for scalability and reliability.

They lower complexity to reduce system outages.
In Exchange Server 2007 you can choose from five server roles, namely Mailbox server,
Hub Transport server, Client Access server (CAS), Unified Messaging server, and Edge Trans-
port server. The following table provides you with an overview as well as the main planning
aspects for each role. More details about the Exchange Server 2007 roles are covered in later
chapters of this book.
TABLE 1.3 Exchange Server 2007 Roles Overview
Server Role Description Planning Aspect
Mailbox server Hosts your mailboxes as well as
public folder databases.
You must plan Exchange servers
at the AD sites where most of the
users are located or depending on
your IT Strategy in key regional
datacenters.
Detailed planning for this role is
covered in Chapters 2 and 9 of
this book.
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