Applies to: Exchange Server 2007 SP3, Exchange Server 2007 SP2, Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2006-09-15

Microsoft Exchange Server 2007 does not support an in-place upgrade from any earlier version of Exchange. The Exchange organization must be operating in native mode before you can start introducing any Exchange 2007 servers into the environment. This means that only Exchange Server 2003 and Exchange 2000 Server servers can exist in the organization. If your organization includes Exchange Server version 5.5, you must perform an upgrade to Exchange Server 2003 or Exchange 2000 Server before moving to Exchange 2007. To move messaging services and data from Exchange Server 2003 or Exchange 2000 Server to Exchange 2007, you must use the move mailbox functionality in Exchange 2007.

Planning a Transition Path

The transition process varies from organization to organization depending on the complexity of the current deployment. The transition process occurs in several phases. Each phase introduces individual Exchange 2007 server roles and features. At the conclusion of each phase, your organization will be running in a supported transition mode. The end-to-end process is designed to maintain messaging functionality and stability throughout the transition process.

Before you start the transition process, we recommend that you assess and document your existing environment. In general, you should document existing settings and configuration information for your Exchange organization, the Active Directory directory service, and your network.

Exchange 2007 Readiness Check

The easiest way to capture most of the information about your Exchange organization, Active Directory, and other settings and configuration information is to scan the organization using the Microsoft Exchange Server Best Practices Analyzer Tool (ExBPA). ExBPA version 2.7 and later includes an Exchange 2007 Readiness Check scan that can be used to assess your organization's readiness for Exchange 2007. As part of that assessment, the organization model is also identified.

After the Exchange 2007 Readiness Check scan is complete, a report is generated. After the report is complete, navigate to the All Issues tab and look for an entry called Transition documentation. Select this item to display the organization model for the scanned Exchange organization.

Table 1 Exchange organization settings

Settings	Information to document
Exchange organization	Mixed or native mode
Exchange server hardware	Processors, memory, disk storage, and network throughput
Exchange Server version	Version and service pack level
Exchange server configuration	Server roles, such as front-end servers, dedicated bridgehead servers, mailbox servers, and public folder servers
Administrative groups	Administrative group names and permissions assigned to Exchange administrators
Administrators	Exchange administrators and any permissions delegation that has been performed
Storage groups and stores	Store configuration, database and log file locations, and any policies that are applied
Data recovery plan	Backup and restore plan
Routing groups	Routing group master, names and locations of servers, connectors and their properties
Policies	Recipient policies, server policies, store policies, and any exemptions that have been applied at the user level
SMTP namespaces	The Simple Mail Transfer Protocol (SMTP) namespace for all domains for which the Exchange organization is authoritative
Global settings for message delivery	Recipient filters, sender filters, address filters, message size limits, and message formats
Message security settings	Virtual server configuration, authentication and encryption settings, and secure relationships with other domains
Antivirus software and settings	Antivirus software installation locations and settings
Anti-spam and antivirus settings	Intelligent Mail Filter spam confidence levels, IP Block List and IP Allow List settings, and attachment blocking settings
Smart host	Complete configuration information that includes IP addresses, authoritative domains, and real-time block list (RBL) subscriptions

Exchange 2007, Exchange Server 2003, and Exchange 2000 Server store the following information in Active Directory:

Data about how the Exchange organization is configured
Schema objects and attributes that are used in Exchange
Recipient information

Exchange 2007 also uses Active Directory sites for routing.

Table 2 describes the Active Directory information that you should collect.

Table 2 Active Directory settings

Settings	Information to document
Active Directory sites	Site names, directory servers in each site, and IP subnets that are associated with each site
IP site links	Sites included in each site link and costs that are assigned to each link
Functional level	Forest and domain functional levels
Expansion servers	Servers that expand distribution list membership and that use one or more global catalog servers to resolve the membership
Security groups	Security groups and security group membership for any groups that have been delegated administrative responsibility for the Exchange organization
Security permissions	Document accounts that are members of Schema Admins and Enterprise Admins universal security groups
Server placement	The location (organizational unit) of each server within the directory service

We recommend that you also document your existing physical network, firewalls, and name resolution servers as part of the Exchange organization upgrade. By documenting these settings, you can identify which locations will provide the most robust connections and optimal bandwidth for server-to-server communication.

Table 3 describes the information that you should collect.

Table 3 Network settings

Settings	Information to document
Physical network	Network backbone, autonomous system connections, and available bandwidth
DNS	DNS servers and Mail Exchanger (MX) records for your organization
Firewalls	Port availability to external and internal systems
Perimeter network servers	Any servers that are located in a perimeter network or screened subnet, and the network services that they provide, especially any servers that provide SMTP-relay functionality

During the planning process, use the information that you have gathered about your existing environment to plan the most efficient and effective transition path for your organization. The transition process for the Exchange organization involves deploying new Exchange 2007 servers and then moving the existing messaging services and data to those servers. After all Exchange Server 2003 and Exchange 2000 Server servers are no longer providing any messaging services to the organization, they can be decommissioned.

Exchange-Aware Products

Any Exchange-aware products in your existing environment, such as anti-virus software, antispam software, backup software, and others, will need to be upgraded to or replaced with newer versions of the software that are compatible with Exchange 2007.

Recommended Transition Process

After performing an Exchange 2007 Readiness Check scan, we recommend that you transition your organization using the following process:

Collect information about your existing infrastructure and perform a readiness check of your organization as described previously.
Deploy and configure Client Access servers. The first Exchange 2007 server role that should be introduced into the organization is the Client Access server. You must deploy the Client Access server role in each Active Directory site that contains or will contain a Mailbox server. This does not mean that every site must contain a Client Access server before you can deploy Mailbox servers. Rather, it means that as each site is deployed, the first role to be deployed is the Client Access server. For more information about deploying the Client Access server role, see Deploying Server Roles, and Post-Installation Tasks.
Deploy and configure Edge Transport servers. The Edge Transport server is deployed outside the Exchange organization in a perimeter network. You can deploy this server role during any phase of the upgrade process. The Edge Transport server does not depend on any particular messaging or directory configuration. You can add an Edge Transport server to an existing Exchange organization without upgrading any Exchange servers. You do not have to make any organizational changes to use an Edge Transport server. For more information about deploying the Edge Transport server role, see Planning for Edge Transport Servers, Deploying Server Roles, and Post-Installation Tasks.
Because the routing topology in Exchange 2007 is very different from the routing topology used in Exchange Server 2003 and Exchange 2000 Server, we recommend that you transition all servers in a routing group to Exchange 2007 at the same time, in the following order:
- Deploy and configure Hub Transport servers. The Mailbox server and Unified Messaging server require a Hub Transport server. You must install and configure a Hub Transport server before mail flow can be established. A Hub Transport server can coexist with Exchange Server 2003 and Exchange 2000 Server servers that have been designated as bridgehead servers for their routing group. However, you must configure connectors to enable mail flow between the Exchange Server 2003 and Exchange 2000 Server routing groups and Exchange 2007 Hub Transport servers. For more information about routing in a mixed environment, see Coexisting with Exchange Server 2003 and Exchange 2000 Server. For more information about deploying the Hub Transport server role, see Planning for Hub Transport Servers, Deploying Server Roles, and and Post-Installation Tasks.
- Deploy and configure Mailbox servers. When Mailbox servers have been deployed, you can move mailboxes from Exchange Server 2003 and Exchange 2000 Server to Exchange 2007. To move mailboxes to Exchange 2007, you can use either the Move-Mailbox cmdlet or the Move Mailbox Wizard. For detailed instructions about how to move mailboxes, see Moving Mailboxes. For more information about deploying the Mailbox Server role, see Deploying Server Roles and Post-Installation Tasks.
- Move resources from Exchange Server 2003 and Exchange 2000 Server servers to Exchange 2007 servers. Resources include public folders and system folders.
- Uninstall Exchange Server 2003 and Exchange 2000 Server. The uninstall process decommissions the servers and removes them from the Exchange organization.
- Remove connectors between routing groups, and then remove the routing groups.
Deploy and configure Unified Messaging servers. The Unified Messaging server is new in Exchange 2007. The Unified Messaging server does not interoperate with earlier versions of Exchange Server. You cannot install and configure a Unified Messaging server until after you have deployed and configured a Hub Transport server and Mailbox server. This is required because messages generated by a Unified Messaging server can only be submitted to a Hub Transport server, and because only recipients who have mailboxes on Exchange 2007 servers can use unified messaging. After you install a Unified Messaging server, there are other deployment tasks that you must complete to successfully deploy unified messaging in your organization. For more information about deploying the Unified Messaging server role, see Deploying Server Roles and Post-Installation Tasks.
Perform post-installation tasks. After deployment of server roles is complete, there are several post-installation tasks that you should perform, including verifying that your installations were successful, and finalizing your deployment. For detailed steps about how to verify that Exchange 2007 was successfully installed, see Verifying an Exchange 2007 Installation.

The transition process is the same for an Exchange Server 2003 or Exchange 2000 Server organization. However, the features that are supported in each version vary. If you will continue to use any features from Exchange 2000 Server that are not supported in Exchange 2007, you must plan to keep at least one Exchange 2000 Server server in your organization. The following Exchange 2000 Server features are not supported in Exchange 2007:

Microsoft Mobile Information Server
Instant Messaging service
Exchange Chat Service
Exchange 2000 Conferencing Server
Key Management Service
cc:Mail connector
MS Mail connector

If you will continue to use any features from Exchange 2003 that are not supported in Exchange 2007, you must plan to keep at least one Exchange 2003 server in your organization. The following Exchange 2003 features are not supported in Exchange 2007:

GroupWise connector
X.400 connector
Connector for Lotus Notes