This
section is not about how to perform common, albeit necessary,
management tasks such as using the interface to add a database.
Instead, it focuses on concepts such as identifying and working with
the server’s functional roles in
the network environment, auditing network activity and usage, and
monitoring the health and performance of your messaging system.
With
each new iteration of Exchange, Microsoft has greatly improved the
tools and utilities used to manage the environment. Exchange 2007 is no
exception. Exchange Server 2007 management can be done locally or
remotely. There are new primary management interfaces, the Exchange
Management Console and the Exchange Management Shell, and new tools and
utilities to assist administrators in the upkeep of their environment.
Managing by Server Roles and Responsibilities
New
in Exchange Server 2007 is the concept of role-based deployment,
allowing administrators to deploy specific server roles to meet the
requirements of their environment. Exchange 2007 provides five distinct
server roles: Edge Transport, Hub Transport, Client Access, Mailbox,
and Unified Messaging.
The Edge Transport Server Role
The
Edge Transport server role is responsible for all email entering or
leaving the Exchange organization. To provide redundancy and load
balancing, multiple Edge Transport servers can be configured for an
organization.
The Edge Transport role is
designed to be installed on a standalone server that resides in the
perimeter network. As such, it is the only Exchange server designed to
NOT be a member of the Active Directory (AD) domain. Synchronization
with Active Directory is provided through the use of Active Directory
Application Mode (ADAM) and a component called EdgeSync.
Edge
Transport servers can provide antispam and antivirus protection, as
well as the enforcement of Edge Transport rules based on Simple Mail
Transfer Protocol (SMTP) and Multipurpose Internet Mail Extensions
(MIME) addresses, particular words in the subject or message body, and
a Spam Confidence Level (SCL) rating. In addition, Edge Transport
servers can provide address rewriting—an administrator can modify the
SMTP address on incoming and outgoing messages.
It
is possible for an organization to avoid the use of an Edge Transport
server completely and simply configure a Hub Transport server to
communicate directly with the Internet. However, this scenario is not
recommended because it exposes your Hub Transport server to potential
attack. The Edge Transport server has a reduced attack surface to
protect against these external threats.
The Hub Transport Server Role
The
Hub Transport role is responsible for managing internal mail flow in an
Exchange organization and is installed on a member server in the AD
domain.
The Hub Transport role handles
all mail flow within the organization, as well as applying transport
rules, journaling policies, and delivery of messages to recipient
mailboxes. In addition, Hub Transport agents can be deployed to enforce
corporate messaging policies such as message retention and the
implementation of email disclaimers.
Hub
Transport servers accept inbound mail from the Edge Transport server(s)
and route them to user mailboxes. Outbound mail is relayed from the Hub
Transport server to the Edge Transport server and out to the Internet.
The
Hub Transport role can be installed on the same hardware with any other
nonclustered internal server role or as a dedicated Hub Transport
server. It can not be installed on the same hardware as an Edge Transport server role.
Each AD site that contains a Mailbox server role must contain at least one Hub Transport server role.
The Client Access Server Role
The
Client Access role is similar to the front-end server in Exchange
2000/2003. Users who are accessing mailboxes via Outlook Web Access
(OWA), Microsoft ActiveSync, Post Office Protocol version 3 (POP3), or
Internet Message Access Protocol version 4 (IMAP4) must connect to the
Client Access server to gain entry. As a matter of fact, for a user to
access an Inbox with any client other than Microsoft Outlook, a Client
Access server must be installed in the Exchange organization.
The Mailbox Server Role
The
Mailbox role will be the most familiar to administrators with previous
Exchange experience. As the name implies, the Mailbox role is
responsible for housing mailbox databases which, in turn, contain user
mailboxes. The Mailbox server role also houses public folder databases
if they are implemented in the environment.
The
Mailbox server role integrates with the directory in the Active
Directory service much more effectively than previous versions of
Exchange allowed, making deployment and day-to-day operational tasks
much easier to complete. The Mailbox server role also provides users
with improved calendaring functionality, resource management, and
Offline Address Book downloads.
The Unified Messaging Server Role
The
Unified Messaging server role is responsible for the integration of
Voice over IP (VoIP) technology into the Exchange messaging system.
When implementing Unified Messaging with Exchange 2007, users can have
access to voice, fax, and email messages all in the same mailbox, and
these messages can be accessed through multiple client interfaces.
