CHAPTER 9
MAPI-BASED CLIENTS
MAPI defines several types of information services, such as address book providers, messages
stores, and transport services, which are configured by means of messaging profiles.
Lesson 1:
Clients for Exchange 2000 Server
A MAPI-based Exchange client is a messaging application that communicates with an Exchange
2000 Server through MAPI and the Exchange transport, which in turn relies on remote procedure
calls (RPCs) to carry out the communication.
MS-DOS-Based Clients
It is not really shocking that an MS-DOS-based Outlook client does not exist. If your
environment still relies on MS-DOS-based computers, you are forced to either use the legacy
Exchange Client or choose another solution, such as Microsoft Terminal Services. Exchange
Client is not the best possible choice because it provides only the basic messaging features.
Just deploy Outlook 2000 on the terminal server and have users connect with the Terminal
Server client. You can find more information about the installation of Outlook 2000 in terminal-
based environments in the Microsoft Office 2000 Resource Kit.
Windows 3.X-Based Clients
Both Exchange Client and Outlook are available for Microsoft Windows 3.x and Microsoft
Windows for Workgroups, and both can communicate with Exchange 2000 Server via RPC
over IPX/SPX and NetBEUI, and if the Windows Sockets (WINSock) interface is installed,
via TCP/IP as well.
IMPORTANT Outlook 2000 is not available for Windows 3.x or Windows for Workgroups,
so you will have to deploy a previous version of Outlook if you cannot use Terminal Services to
provide your users with access to the latest clients over the network.
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Windows-Based (32-Bit) Clients
Although 32-bit Exchange Clients for Microsoft Windows 95 and Microsoft Windows NT
exist, you should not consider deploying them on Windows 95/98, Windows NT, or Microsoft
Windows 2000.
Migration from Exchange Client 4.0/5.0
Microsoft Outlook 97 was designed to completely replace the Exchange Client family. Outlook
2000, representing the third Outlook generation, replaces Exchange Client even better.
Upgrading is easy, so if you are still running Exchange Client 4.0 or 5.0, consider a migration
to Outlook 2000. After migration, you can continue to use all existing message folders,
custom views, electronic forms, and some of the legacy client extensions.
Outlook can use the same MAPI profile that might already have been created for Exchange
Client, which simplifies the migration process significantly.
Migration from Schedule
When migrating from Schedule+7.x to Outlook 2000, you need to import the existing
Schedule+ information onto Outlook explicitly if you want to keep it available. Differences
exist in the way Outlook stores the items: Whereas Schedule+ uses a hidden folder on the
server-based mailbox and a synchronized local calendar file (.scd), Outlook maintains the
information using the Calendar, Contacts, Tasks, Journal, and Notes folders in the user’s
mailbox.
Macintosh-Based Clients
Windows 2000 Server systems are accessible for Apple Macintosh computers provided the
Services for Macintosh have been installed. Because Exchange 2000 Server integrates tightly
with Windows 200 Server functionality, it benefits from this connectivity and offers Macintosh
clients access to server-based resources. Therefore, Exchange Client, Schedule+, and
Outlook for Apple Macintosh computers are available. Both Exchange Client and Outlook
can communicate with the Exchange Server using the AppleTalk protocol or TCP/IP, so
configure Outlook with whichever protocol is supported on your network.
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Outlook for Macintosh
The Outlook bar can be customized, and the folder banner allows you to group message
items as you want.
Client Limitations
Not all Windows-based client features are supported on the Macintosh platform. For example,
electronic forms can’t be launched because MAPI doesn’t exist. You can’t use any of the MAPI
information services, and integrated remote mail functionality is not available. Hence, you’ll need
to ensure that local area network (LAN) connections exist between the Macintosh clients and
Exchange 2000 Server. The personal folder stores (.pst files), which are used to keep the
messages on the client computer, cannot be interchanged with Windows-based .pst files,
and Advanced Security features are limited to the local organization.
Lesson 2:
Messaging Application Programming Interface
MAPI is only a specification and not a messaging system in and of itself. It provides only a
common way to access messaging backbones.
MAPI Subsystem
MAPI defines standardized interfaces at two layers, which allows the creation of client
applications and the development of information services. The client-side specification is
called the client interface, and the system-side specification is known as the service
provider interface.
MAPI Advantages
The MAPI subsystem provides may advantages over system-specific interfaces because
it frees the developer from learning how to program different messaging systems separately.
The following are the advantages of MAPI:
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MAPI Subsets
To simplify messaging programming, the MAPI client interface has been broken down into
several subsets. Available subsets are:
CDO was formerly known as Active Messaging. The entire client interface is sometimes
called Extended MAPI. All programming interfaces are documented in the Microsoft
Platform System Development Kit.
Information Store
Information Services reside on the lower level of the MAPI subsystem at the level of the
service provider interface. They are separated into transport services, address books,
and message stores.
Address Books
An Address book provider maintains and provides information about recipient objects
to the client. The address book provider is an essential component of the MAPI
subsystem because without available recipient objects, it would be impossible to
send newly composed messages.
Server-Based Address Books
The server-based address book contains the recipient objects that exist within the Exchange
organization, specifically Active Directory directory service. EMSABP32.DLL maintains
this service, which is part of the Exchange transport driver.
Offline Address Book
The offline address book—also maintained by the Exchange transport service
(EMSABP32.DLL)—contains a local copy of the server-based global address list.
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Personal Address Book
The personal address book is maintained within a local .pab file by MSPST32.DLL,
which represents the personal address book and the personal folder store service.
Outlook Address Book
The Outlook address book implemented in CONTAB32.DLL provides similar functionality
to the personal address book, but maintains the address information in Contacts folders
rather than a local .pab file.
NOTE: It is advisable to use the Contacts folder and the Outlook address book instead
of local .pab files to maintain your personal e-mail address information.
Message Repositories
MAPI-based clients generally store e-mail messages, word processing documents,
spreadsheets, voice mail files, electronic forms, and other items in folder structures,
which can reside on a server or the local computer. Based on their purpose, these
folders are named public, private, offline, or personal folders.
Private folders refer to those folders that reside on a user’s server-based mailbox and
are typically available to only one user.
Message Store Providers
EMSMDB32.DLL is involved if you are working with items stored on an Exchange 2000
server. EMSMDB32.DLL is part of the Exchange transport service and provides the
services required for accessing public folders and the private folders of your mailbox.
EMSMDB32.DLL is also involved if you are working with an offline folder store.
Transport Providers
A message transport provider is responsible for physical message delivery. This service
takes outgoing messages from the MAPI subsystem and transfers them to the underlying
messaging backbone to which it corresponds.
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Lesson 3:
Creating Messaging Profiles
The installation of a MAPI-based client is usually performed in two stages: In the first
stage the Setup program copies the client files to the local hard disk. The second stage,
the creation of a messaging profile must also be completed.
Messaging Profiles
One of the primary goals of the MAPI subsystem is to provide access to various messaging
systems, either simultaneously or in separate sessions. To meet this goal, messaging profiles
are used. A messaging profile, sometimes also called a MAPI profile, is the set of those
information service that should be activated during a particular session. All required
configuration settings are stored in the profile.
Setup Wizard
The Microsoft Outlook Setup Wizard guides you through the process of configuring a messaging
profile and can be launched in a variety of ways. The Setup Wizard also appears if no profile
exists when you start Outlook. The client is unable to operate without a valid profile, so the
wizard prompts for all the required information to create a valid messaging profile before the
actual client is launched.
Multiple Profiles
The MAPI subsystem is able to use only one profile at a time; however, more than one profile
can be created on the same computer. One profile might connect you to your mailbox on
Exchange 2000 Server, and another might connect you to an Internet service provider, but
only one profile will be activated at any particular time.
Multiple Users
Windows 95, Windows NT, and Windows 2000 provide support for multiple users who share
a single computer because these operating systems can maintain messaging profiles on a per-user
basis.
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Automatic Profile Generator
The Automatic Profile Generator (NEWPROF.EXE) is an installation tool that uses a profile
descriptor file (.prf) to create MAPI profiles for users. There are the following options:
P. References the complete path to the .prf descriptor file.
S. Provides a user interface to select the .prf file and to display status and error messages.
Displays MAPI status codes in case any errors are encountered. Can only be used in
conjunction with the –S switch.
Executes NEWPROX.EXE –S automatically without user interaction. Requires the
–P<Path to the .prf file> switch.
Profile Descriptor File
A good starting point could be the OUTLOOK.PRF that comes with the Microsoft Office
2000 Resource Kit. Edit OULOOK.PRF to modify the line ProfileName=Microsoft
Outlook in the [General] section.
Exercise Summary:
default profile, after which the client can start successfully. Messaging profiles are
stored in the Registry under the HKEY_CURRENT_USER hive.
Personal Folder Configuration
The personal folder store allows you to work with personal folders in the same way you work
with private or public folders on Exchange 2000 Server.
In this way, older messages can be copied to a .pst file, archived individually and deleted from
he Exchange 2000 server.
NOTE: A .pst file can contain up to 64,000 entries and can grow to a maximum size of 2GB.
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Personal Folder Security
It is possible to specify an encryption algorithm for personal folders stores. Depending on the
security level you need, you can select the options No Encryption, Compressible Encryption, and
Best Encryption when creating a .pst file.
You might forget your password as time passes, and you are not prompted for it. You will still
be able to use the .pst file because the password is saved in the messaging profile. You will,
however, have a problem if you need to create a new profile that must include the old .pst file.
Assigning a Location for Incoming Mail
When you configure a personal folder store and connect to Exchange 2000 Server via the
Exchange transport service at the same time, two mail repositories exist within your messaging
profile, the personal folder store and your server-based mailbox.
Exercise Summary:
folders.
Offline Folder Configuration
Offline folders are the basis of a process known as local replication. The folders are
local copies of server-based message folders.
NOTE: The offline folders store and the offline address book, as implemented in the
Exchange transport service—allows you to work while disconnected from the server.
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Local Replication Example
Let’s say you have configured an offline folder store to synchronize your server-based
folders Calendar, Contacts, Deleted Items, Inbox, Journal, Notes, Outbox, Sent Items,
and Tasks.
Configuring Offline Folders
You can configure the offline folder store through the Exchange transport service’s property
sheets within a messaging profile. You can display these property sheets through the Services
command on the client’s Tools menu.
IMPORTANT An .ost file (by default, \Winnt\OUTLOOK.OST) might already
exist if you answered Yes to the question Do You Travel With This Computer? During
the profile creation within the Profile Wizard. An .ost file is associated with a profile.
If you create a new profile, you will need to create and synchronize a new .ost file before
it can be used with the new profile.
Configuring Message Folders to be Available Offline
Using Outlook 2000, you can configure the local replication of server-based messages folders
via the Mail Service property sheet of the Options dialog box. If you have created an .ost
file beforehand, you can click on the Offline Folder Settings button to specify the folders for
offline user.
TIP If you want to configure a public folder for local replication, you must first drag the
folder to the Favorites container. You can then configure it the same way you configure
private folders.
Synchronization Capabilities
You should force the synchronization between the server-based folders and the local replica
of folders once they have been included in the local replication.
Outlook 2000 can also synchronize folders automatically. This will happen whenever Outlook
2000 is started on online mode, and according to the settings that you can specify in the Mail
Services tab of the Options dialog box.
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Filtering Offline Folders
Examining the synchronization capabilities of Outlook 2000 in more detail, there is a wide
selection of options to selectively download messages that meet certain criteria. Especially
when working on slow dial-up connections, you might want to configure Download Options
and Folder Filters in the Offline Folder Settings dialog box to selectively synchronize existing
items.
Offline Address Book Configuration
When you examine the Offline Folder Settings dialog box, you will see the Download Offline
Address Book check box, which allows you to include the download of address book
information into the folder synchronization process.
Manual Address Book Download
When enabled, the Download Offline Address book check box allows automatic downloading
of the address book as part of the Outlook synchronization cycle. You can also download the
address book from the server manually at any time. By default, your Global Address List
(GAL) is available for download, but you may configure additional offline address books in
the Exchange System Manager.
Address Book Details
To reduce the size of the address book downloaded to your machine and therefore reduce
transmission time, you can choose to download the address book without details that are
not required for message creation and addressing.
Offline Address Book Files
The offline address book (.oab) files are usually stored in the current Windows directory.
At a minimum, four .oab files are always downloaded, but the fifth file is available for
downloading you also have specified the retrieval of address details.
The ANRDEX.OAB file provides indexes for Ambiguous Name Resolution. The
RDNDEX.OAB file helps to manage e-mail addresses. Address book templates are
copies to TMPLTS.OAB. Address details are kept in the DETAILS.OAB and
BROWSE.OAB files. DETAILS.OAB is usually the largest file because it keeps
all the detailed information about the users of your organization.
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IMPORTANT The Download Changes Since Last Synchronization option must be
deselected if you want to ensure that the DETAILS.OAB file will be deleted.
Selecting only the No Details option from the Offline Address Book dialog box is
not sufficient.
Lesson 4:
Advanced User Configuration
In a typical Exchange 2000 environment, many different kinds of Outlook users
cooperate and share information. Typical users work with only one (personal)
workstation that is directly connected to the organization’s computer network.
Remote users, on the other hand, many work primarily offline using a modem or
Integrated Service Digital Network (ISDN) card to establish connections for
sending and downloading messages.
Roving User Support
To simplify the task of creating messaging profiles for roving users, you can implement
server-based profiles that will be copied to every workstation a roving user logs on to,
automatically providing the same messaging environment to the user.
Roaming Profiles
Windows 95/98, Windows NT, and Windows 2000 provide built-in support for roving
users because MAPI-based clients store their messaging profiles within the user’s
context in the workstation’s Registry.
Personal Folder Store Considerations
Roving users typically want access to all their messages from within any messaging
client they are using. If they have stored some of their messages in one or more
personal folder stores, precautions must be taken to make sure the associated .pst
files are all available over the network. Therefore, .pst files should be placed on a
file server that can be accessed by every client machine.
Outlook Web Access or Terminal Services
The HTTP-based access to server-based mailboxes is an alternative to all other roving
user options. By using a regular Web browser that support JavaScript and frames
(such as Microsoft Internet Explorer 5.0), users can gain access to their mailbox
through Outlook Web Access (OWA).
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Terminal Services allows you to run Outlook 2000 on a server over the network or
a dial-up connection from any workstation that is running the Terminal Services client
software. From Outlook’s point of view, users running Terminal Services client
software are not considered roaming users because they are using the same
environment on the terminal server every time they connect. It is more like they
would work with a single virtual workstation but multiple keyboards and monitors.
Remote User Support
Users who work via modem or ISDN lines usually don’t work online continuously.
They compose new messages and read downloaded messages while disconnected
from the server.
Remote Mail Versus Offline Folders
You cannot use the remote mail features of Outlook 2000 if an offline message store
has been configured. In this situation, you must disable the offline message store before
using remote mail. However, because Outlook 2000 offers far-reaching configuration
and filter capabilities for synchronizing server-based folders and because the offline
folder approach is usually less complex to handle than the remote mail features, you
should consider using offline folders instead of remote mail.
Remote Mail Configurations
Outlook 2000 allows you to configure remote mail connections through the property
sheets of the Exchange transport service, which in turn relies completely on the dial-up
networking capabilities of the operating system.
Remote Mail Connections
A connection to your Exchange 2000 server is established when you click Connect under
the Remote Mail option on the Tools menu. While this connection is up and running, the
headers of messages in your server-based mailbox are downloaded, and the messages
composed offline are uploaded.
Based on the retrieved header information, you can select which messages to mark for
retrieval. This will move the messages to your local store the next time you connect.
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Scheduled Connections
If you want to automate the processes of establishing a connection and processing marked
items, you can configure scheduled connections through the Remote Mail property sheet of
the Exchange transport service. During automatically established connections, the client
behaves the same way as during manually started remote mail connections.
Exercise Summary:
menu, which displays a submenu and allows you to launch the Remote Connection Wizard
through the Connect command.
Chapter Summary:
information services, such as address book providers, message stores, and transport
services, that should be used in a particular client session.
profiles, which is the basis of roaming user support.
transport service.
disconnected from the computer network.
functionality of Outlook 2000 to download messages, or create an .ost file and
synchronize this offline repository with your server-based messaging folder.