The functional level of Windows 2003

Source: Internet
Author: User
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In order to adapt to the development of the times, there are many companies to upgrade the Windows NT domain of internal server to a higher version, which involves the problem of ad migration. What are the advantages of a more advanced domain environment? In the case of Windows AD domain, it provides an extensible database schema, a domain controller for multiple primary domains, a trust relationship for automatic two-way delivery, and so on. If you migrate ad to a Windows Server 2003 domain, you can enjoy more enhanced performance and scalability, such as providing a logical hierarchical organization of directory information to make it easier for administrators to design, deploy, and manage your organization's catalogs more flexibly.

Domain level

If you have already deployed Windows \ Active Directory, you must be familiar with the concept of domain mode. With Windows up Active Directory, there are two domain modes to choose from:

Blending mode (default setting): Its network configuration uses any combination system of Windows 2000 and Windows NT. Windows 2000 domain controllers and Windows NT 4.0 backup domain controllers can coexist seamlessly in the same domain without any problems.

Native mode: Domain controllers in a domain can only run Windows 2000 systems. In this mode, you can enjoy some additional features, such as group nesting features and all directory service functions.

Once you upgrade to Windows Server 2003, the type of domain mode becomes richer. In addition to the functional levels that are similar to the two domain modes of Windows 2000, the additional two domain functional levels reflect the advantages of Windows Server 2003 domain controllers (note: Windows 2003 server's domain functional level and Windows The "domain Mode" of 2000 is a concept). There are four domain-level choices for Windows Server 2003 AD domains:

Windows 2000 mixed domain level (default): As the name suggests, its functional level is almost identical to the "mixed mode" of Windows 2000, except that it is suitable for Windows 2000 and Windows NT, as well as Windows Server 2003 domain controller.

Windows 2000 native domain level: its functional level is similar to "native mode" of Windows 2000, and the only difference is that all domain controllers in the domain can run Windows Server 2003 or Windows 2000.

Windows Server 2003 transition domain level: Allows Windows 2003 domain controllers to be mixed with Windows NT4 domain controllers, but not with Windows 2000 domain controllers.

Windows Server 2003 domain level: At the 4 domain level, it has the highest functional level, although all domain controllers in the domain can only run Windows Server 2003. You can enjoy the full features and functionality provided by the Windows Server 2003 AD domain.

Forest level

Once the Windows Server 2003 domain controller in the domain is deployed, you will need to select the functional level of the forest. There are three levels to choose from:

Windows 2000 forest level (default): This forest functional level is similar to the Windows 2000 domain level under the default settings. The forest functional level, which belongs to the default state, provides the most basic forest structure characteristics and functions.

Windows Server 2003 transition forest level: As far as the functional level is concerned, it is similar to the Windows Server 2003 domain level. In other words, only Windows Server 2003 domain controllers and Windows NT domain controllers can be added to the forest. You can enjoy the replication improvements and new properties that are provided by the global catalog server.

Windows Server 2003 forest level: This is one of the most functional forest configurations that can enjoy the full range of features and functionality, including cross forest trusts. A domain controller that is added to the forest can only run Windows Server 2003, and all domains in the forest must be set to the highest functional level of Windows Server 2003 domain.

What kind of functional level is appropriate for an enterprise's web domain?

The advantages and disadvantages of the four domain functional levels are listed below, and you can choose from the company's own needs.

Windows 2000 mixed-domain level: This domain level is clearly the best choice for businesses that do not completely eliminate Windows NT domain controllers. Its biggest drawback is that Microsoft is slowly cutting back its support services for Windows NT since the end of 2004.

Windows 2000 native domain level: If you have deployed AD migrations from Windows NT to Windows 2000, this level of functionality is clearly the best for you. Its biggest feature is that it is only suitable for upgrading from a Windows NT environment to Windows see Active directory.

Windows Server 2003 transition domain level: It turns out that Windows Server 2003 is a very stable operating system that, if you want to one-step, upgrades Windows NT environments directly to Windows 2003 Active Directory, you should select this domain level. Its biggest feature is that Windows 2000 domain controllers are not allowed in a domain.

Windows Server 2003 domain level: For small companies or businesses, it is best to choose this domain functional level if you plan to convert the signal domain to the Windows 2003 functional level before converting the forest. It has only one small flaw: it requires the entire forest, domain controllers in each domain can only run Windows Server 2003.


Both the domain and forest functional levels have a greater choice, whether it is Windows 2003 Active Directory or Windows Server Active Directory. Before making a decision, you should first choose the operating system version that is best suited to your company's current and future needs. Then, refer to the above description of the functional level to set up domains and forests.

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