Article ID: 270143 - View products that this article applies to.
This article was previously published under Q270143
This article is a consolidation of the following previously available articles: 829577, 822446 and 830184
A Microsoft Exchange 2000 Server or Microsoft Exchange Server 2003 organization runs in one of two modes of operation: mixed mode or native mode. This article describes the differences between mixed mode and native mode.
Mixed modeAn organization that is running in mixed mode can handle all versions of Exchange Server. By default, Exchange 2000 Server and Exchange Server 2003 are installed in mixed mode.
Mixed mode organizations have the following characteristics:
To other Microsoft Exchange Server 4.0, 5.0, and 5.5 computers in the site, the Exchange 2000 Server or Exchange Server 2003 computer appears as just another server. The servers send out directory replication notifications as usual. Also, the SRS database requests changes just like earlier versions of Exchange Server request changes.
Mixed mode exists to maintain backward compatibility. However, mixed mode limits the system to the constraints that are imposed by earlier software releases. In a mixed mode site, the rules that apply to earlier versions of Exchange Server also apply to Exchange 2000 Server or Exchange Server 2003.
The following limitations apply to Exchange 2000 Server or to Exchange Server 2003 in a mixed-mode environment:
Native modeAn organization that is running in native mode can contain only Exchange 2000 Server or later computers. New Exchange Server 5.0 or 5.5 computers cannot be introduced into the organization.
When you have a configuration with Windows 2000 domain controllers and global catalog servers on the local network, these servers must have Windows 2000 Server SP3 or later installed if the domain controllers and global catalog servers will communicate with the Exchange Server computer or with Active Directory Connector (ADC).
You can change an Exchange 2000 Server or Exchange Server 2003 organization to native mode after all the servers are upgraded to Exchange 2000 Server or to Exchange Server 2003 and if earlier release restrictions no longer apply. You cannot switch to native mode until you either upgrade or decommission all earlier versions of Exchange Server.
The following are some of the features of Exchange 2000 Server or Exchange Server 2003 native mode:
How to determine the mode in which the Exchange Server organization is runningBy default, an Exchange 2000 Server or Exchange Server 2003 organization runs in mixed mode. To determine the mode in which the Exchange 2000 Server or Exchange Server 2003 organization is currently running, follow these steps:
How to change modesNote Before you can change an organization from mixed mode to native mode, all of the computers in the organization must be running Exchange 2000 Server or Exchange Server 2003. Before you can upgrade computers that are running Exchange Server 4.0 or 5.0 to Exchange 2000 Server or Exchange Server 2003, you must upgrade these computers to Exchange Server 5.5 Service Pack 3. Exchange Server 4.0 and 5.0 cannot be upgraded directly to Exchange 2000 Server or Exchange Server 2003.
Important After you change to native mode, you cannot change back to mixed mode. This conversion is a one-time conversion. You must fully understand the results before you continue with the conversion.
After you upgrade or remove all versions of Exchange Server that are earlier than Exchange 2000 Server, you can switch the Exchange 2000 Server or Exchange Server 2003 organization to native mode by using Exchange System Manager:
For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/272314/ )XADM: Preparing a mixed mode organization for conversion to native mode
(http://support.microsoft.com/kb/327779/ )How to convert from mixed mode to native mode in Exchange
For more information about switching an Exchange organization to native mode, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/281088/ )XADM: When to Change an Exchange Organization to Native Mode
For more information about UDG users cannot access PF in a mixed-mode Exchange 2000 or Exchange 2003 environment, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/898082/ )Users cannot access public folder resources that are members of a nested Universal Distribution Group (UDG) in a mixed-mode Exchange Server environment