Introduction - Microsoft Exchange Server 2003 ActiveSync Architecture White Paper October 2020

Introduction
Microsoft Exchange Server 2003 allows wireless devices such as a browser-enabled cell phones or Microsoft Windows Mobile™–based PDAs to access corporate Exchange Server information. Mobile users gain full access to mail, calendar, and contacts without the need for a desktop computer and retain access to this information while offline. All changes made on the wireless device are reflected in the live mailbox and can be seen from a full desktop mail client such as Microsoft Office Outlook® or Outlook Web Access.
Motorola and Microsoft have created an alliance to provide a wireless solution based on Motorola phones running the Windows Mobile software for Smartphones. This document describes the following aspects of integrating the Windows Mobile software and Exchange Server 2003 infrastructure:
Exchange Server 2003 requirements and typical implementation
Motorola’s test and production implementations
Infrastructure changes to support Exchange Server 2003 Microsoft ActiveSync® technology in various environments
Additional infrastructure benefits when you add the Exchange Server 2003 capability
For detailed information about Exchange Server 2003 mobile capabilities, please see the “Mobile Access Using Microsoft Exchange Server 2003” white paper, at http://www.microsoft.com/exchange/techinfo/outlook/MobileAcc.doc
The Exchange Server 2003 ActiveSync User Experience
Laptop computers enable mobile users to work in multiple locations such as work, home, a hotel, a customer’s office; however, limitations in battery life and network access mean it’s not always possible for a laptop to stay in constant use. Also, one cannot use a laptop when, for example, in a store or restaurant, driving a car, or out with colleagues, family, and friends.
Mobile phones are portable, have a long enough battery life to be used all day, and offer wide-ranging network coverage. Motorola and Microsoft have formed a partnership to introduce the new Microsoft Windows Mobile–based MPx200 Smartphone. Combined with Exchange Server 2003 ActiveSync, this phone allows users full access to corporate e-mail while away from the office.
The Windows Mobile–based Motorola MPx200 Smartphone is a mobile communications tool that is ideal for busy corporate executives, sales people, managers, field engineers, and so on who need to stay in close touch with e-mail while on the move. The MPx200 Smartphone uses the familiar Microsoft Windows® interface in a powerful and small package so that the user can respond to important and urgent e-mail in a timely way to meet the demands of today’s competitive environment.
When disconnected from its partner laptop or desktop, the MPx200 Smartphone can run ActiveSync to synchronize mail, contacts, and calendar entries by using a wireless General Packet Radio Services (GPRS) connection.
The Motorola MPx200 Smartphone includes an e-mail client, allowing e-mail to be sent and received on the move. Each time ActiveSync is run on the phone, the client synchronizes with the Exchange Server 2003 mailbox server. Newly composed mail is sent, and new mail that has arrived at the server is received. Mail that is read or deleted using the Smartphone is marked appropriately as read or deleted on the Exchange Server 2003 mailbox server and is shown with this status on a primary mail client such as Outlook.
In addition to handling e-mail, the MPx200 Smartphone synchronizes calendar and contact entries. Contact entries make it easy to send new mail to colleagues and customers. Mail can be composed and correctly addressed while offline and is sent when ActiveSync next runs on the phone. Synchronization of calendar entries allows the phone to give a timely reminder for meetings and personal appointments. The calendar entry can be opened to see details of a meeting room or conference call. New calendar entries can be created on the phone and are then visible from Outlook.
Exchange ActiveSync Requirements and Typical Implementation
Exchange
Exchange Server 2003 mailbox server.
Exchange Server 2003 front-end server (optional but particularly recommended for mobile access to multiple back-end mailbox servers).
All Exchange Server 2003 servers must run on either Microsoft Windows 2000 Server or Microsoft Windows Server™ 2003 operating system. (Windows Server 2003 is recommended for best performance.)
All Microsoft Active Directory Connector Services should be running the Exchange Server 2003 version of the Active Directory Connector (only applicable if connecting with an Exchange 5.5 environment).
Previous versions of Exchange Server required a secondary server (such as Microsoft Mobile Information Server or a non–Microsoft synchronization server) to support wireless devices. Exchange Server 2003 has mobile capabilities built in and uses Exchange Server 2003 ActiveSync technology to provide fully synchronized e-mail directly to mobile clients. Clients can continue to read and send mail while offline and then sync through a wireless Internet connection.
Active Directory
Exchange Server 2003 servers must be members of a Windows Active Directory® directory service domain.
Active Directory Domain Controllers must run on either Windows 2000 Server with Service Pack 3 (SP3) or Windows Server 2003. (Windows Server 2003 is recommended for best performance.)
In older Exchange product versions, user accounts are entries in the Microsoft Windows NT® 4.0 operating system domain SAM, and Exchange mailboxes are objects in the Exchange 5.5 directory. Both Exchange 2000 and Exchange 2003 use Active Directory as a single common directory. There is no directory on each Exchange Server instance. In Active Directory, users and mailboxes are a single object class that includes both user attributes and mailbox attributes, including the password. Similarly, Exchange Server distribution lists are implemented as Active Directory groups.
For Exchange Server 2003 ActiveSync, Active Directory authenticates the incoming connection from the Internet and the user’s Active Directory identity authorizes access to the user’s mailbox.
Before installing the first Exchange Server 2003 instance, the following steps are required:
Run Exchange Server 2003 ForestPrep to make the required schema context and configuration context changes in Active Directory.
Run Exchange Server 2003 DomainPrep in each domain supporting Exchange Server 2003 servers or users with Exchange Server 2003 mailboxes.
Upgrade all Active Directory Connector instances to the Exchange Server 2003 version.
Wireless Mobile devices
Phones running Windows Mobile 2002 or 2003 software for Smartphones, such as the Motorola MPx200
Windows Mobile–based PDAs using Windows Mobile 2002 or 2003 software for Pocket PC Phone Edition
Other phones compatible with Exchange Server 2003 ActiveSync
Devices running the Windows Mobile 2003 operating system will additionally support the up-to-date notification feature. Up-to-date notifications combined with over-the-air synchronization mean that Exchange ActiveSync–enabled devices can be automatically kept up-to-date. (This feature is supported only on Windows Mobile 2003–based devices.) When a new message arrives in a user’s Inbox, Exchange 2003 sends a notification to mobile operators, which in turn alert the device and instruct it to begin synchronization. Thus, the device is up-to-date when the user needs it. In addition, the user can set additional preferences for peak and off-peak times to customize the notification process. Devices running the 2002 operating system version can closely simulate this by being set to automatically run ActiveSync several times per hour.
Devices must be configured as follows.
Phone basics Configure security PIN and time zone
Data connection Add GPRS connection.
Exchange Server connection Windows Active Directory user name and password; Domain Name System (DNS) name for external mail access
ActiveSync options Calendar, contacts, mail
Internet connectivity and security
A Smartphone or Windows Mobile–based PDA makes an ActiveSync connection from the Internet into a corporate Exchange server. The incoming Internet connection requires:
A wireless mail DNS name resolvable from the Internet—for example, wireless-mail.myco.com
Port 443 Secure Sockets Layer (SSL) Secure HTTP (HTTPS) opened at the external firewall
SSL certificates on servers terminating SSL and translating HTTPS to HTTP
A proxy server such as Microsoft Internet Security and Acceleration (ISA) Server 2000 to intercept incoming Web requests from clients and redirect them to the Exchange Server 2003 mailbox server or front-end server (if used). ISA can perform content inspection and filtering and can use the URLScan feature to check the incoming requests for valid commands and to reject buffer overflow attacks.
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