The Active Directory schema defines the kinds of objects, the types of information about those
objects, and the default security configuration for those objects that can be stored in Active
Directory.
The Active Directory schema contains the formal definitions of all objects, such as users,
computers, and printers that are stored in Active Directory. On domain controllers running
either Windows 2000 or Windows Server 2003, there is only one schema for an entire forest.
This way, all objects that are created in Active Directory conform to the same rules.
The schema has two types of definitions: object classes and attributes.
Object classes such as user, computer, and printer describe the possible directory objects that
you can create. Each object class is a collection of attributes. Attributes are defined separately
from object classes. Each attribute is defined only once and can be used in multiple object
classes. For example, the Description attribute is used in many object classes, but is defined
only once in the schema to ensure consistency.
The schema is the Active Directory component that defines all the objects and attributes that the directory service uses to store data.
From active directory schema snap-in.But before that you have to register the schmmgmt.dll file by using regsvr32.exeschmmgmt.dll @ cmd prompt
Using the Active Directory Schema snap-in, add an attribute to the user accountproperty for Employer ID Code.
An active directory schema allows the user to perform a detailed search for an individual, place or other piece of information. A well designed schema represents software that gives the user access to information within an organization. The structure becomes more detailed as the schema becomes detailed.
A collection of domains that share a common schema.
Active Directory NC (Naming Context's)Active Directory consists of three partitions or naming contexts (NC) Domain, Configuration and Schema Naming ContextsEach are replicated independentlyAn Active Directory forest has single schema and configuration Every domain controller (DC) holds a copy of each (schema, configuration NC's)Forest can have multiple domains Every domain controller in a domain holds a copy of the domain NC
Active Directory NC (Naming Context's)Active Directory consists of three partitions or naming contexts (NC) Domain, Configuration and Schema Naming ContextsEach are replicated independentlyAn Active Directory forest has single schema and configuration Every domain controller (DC) holds a copy of each (schema, configuration NC's)Forest can have multiple domains Every domain controller in a domain holds a copy of the domain NC
schema attributes
A collection of domains that share a common schema
Active Directory NC (Naming Context's) * Active Directory consists of three partitions or naming contexts (NC) ** Domain, Configuration and Schema Naming Contexts * Each are replicated independently * An Active Directory forest has single schema and configuration ** Every domain controller (DC) holds a copy of each (schema, configuration NC's) * Forest can have multiple domains ** Every domain controller in a domain holds a copy of the domain NC
No updates to the Active Directory schema will be possible. Since schema updates are rare (usually done by certain applications and possibly an Administrator adding an attribute to an object), then the malfunction of the server holding the Schema Master role will not pose a critical problem.
The Schema and Configuration partition