Although the Exchange server is a powerful systems
component, it is only half the equation for an email platform. The
client systems comprise the other half, and are a necessary ingredient
that should be carefully determined in advance.
Outlining Client Access Methods
Great effort has been put
into optimizing and streamlining the client access approaches available
in Exchange Server 2010. Not only have traditional approaches such as
the Outlook client been enhanced, but support for nontraditional access
with POP3 and IMAP clients is also available. The following options
exist for client access with Exchange Server 2010:
Outlook MAPI—
Traditional MAPI access has been replaced with MAPI on the Middle Tier
(MoMT), which enables Outlook clients to communicate through the CAS
servers. Outlook versions that support access to Exchange Server 2010
servers are limited to the 2003, 2007, and 2010 versions of Outlook.
Outlook Web App (OWA)—
The Outlook Web App (OWA) client is now nearly indistinguishable from
the full Outlook client. The one major component missing is offline
capability, but nearly every other Outlook functionality is part of OWA.
ActiveSync—
ActiveSync provides for synchronized access to email from a handheld
device, such as a Pocket PC, Windows Mobile, iPhone, or other
ActiveSync-enabled device. It allows for real-time send and receive
functionality to and from the handheld, through the use of push
technology.
Outlook Anywhere—
Outlook Anywhere (previously known as RPC over HTTP) is a method by
which a full Outlook client can dynamically send and receive messages
directly from an Exchange server over an HTTP or Hypertext Transfer
Protocol Secure (HTTPS) web connection. This allows for virtual private
network (VPN)–free access to Exchange Server data, over a secured HTTPS
connection.
Post Office Protocol 3 (POP3)—
The Post Office Protocol 3 (POP3) is a legacy protocol that is
supported in Exchange Server 2010. POP3 enables simple retrieval of mail
data via applications that use the POP3 protocol. Mail messages,
however, cannot be sent with POP3 and must use the SMTP engine in
Exchange Server. By default, POP3 is not turned on and must be
explicitly activated.
Internet Message Access Protocol (IMAP)—
Legacy Interactive Mail Access Protocol (IMAP) access to Exchange
Server is also available, which can enable an Exchange server to be
accessed via IMAP applications, such as some UNIX mail clients. As with
the POP3 protocol, IMAP support must be explicitly turned on.
Note
Exchange Server 2010
supports the option of disallowing MAPI access or allowing only specific
Outlook clients MAPI access. This can be configured if an organization
desires only OWA access to an Exchange server. It can also, for security
reasons, stipulate that only Outlook 2007 and Outlook 2003 can access
the Exchange server. The Registry key required for this functionality is
the following:
Location:HKLM\System\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
Value Name: Disable MAPI Clients
Data Type: REG_SZ
String: Version # (i.e. v4, v5, etc)
http://support.microsoft.com/default.aspx?scid=KB;EN-US;288894
Each organization
will have individual needs that determine which client or set of clients
will be supported. In general, the full Outlook client offers the
richest messaging experience with Exchange Server 2010, but many of the
other access mechanisms, such as Outlook Web App, are also valid. The
important design consideration is identifying what will be supported,
and then enabling support for that client or protocol. Any methods that
will not be supported should be disabled or left turned off for security
reasons.
