1.1 Glossary

This document uses the following terms:

Active Directory: The Windows implementation of a general-purpose directory service, which uses LDAP as its primary access protocol. Active Directory stores information about a variety of objects in the network such as user accounts, computer accounts, groups, and all related credential information used by Kerberos [MS-KILE]. Active Directory is either deployed as Active Directory Domain Services (AD DS) or Active Directory Lightweight Directory Services (AD LDS), which are both described in [MS-ADOD]: Active Directory Protocols Overview.

backup domain controller (BDC): A domain controller (DC) that receives a copy of the domain directory database from the primary domain controller (PDC). This copy is synchronized periodically and automatically with the primary domain controller (PDC). BDCs also authenticate user logons and can be promoted to function as the PDC. There is only one PDC or PDC emulator in a domain, and the rest are backup domain controllers.

domain: A set of users and computers sharing a common namespace and management infrastructure. At least one computer member of the set has to act as a domain controller (DC) and host a member list that identifies all members of the domain, as well as optionally hosting the Active Directory service. The domain controller provides authentication of members, creating a unit of trust for its members. Each domain has an identifier that is shared among its members. For more information, see [MS-AUTHSOD] section 1.1.1.5 and [MS-ADTS].

domain controller (DC): The service, running on a server, that implements Active Directory, or the server hosting this service. The service hosts the data store for objects and interoperates with other DCs to ensure that a local change to an object replicates correctly across all DCs. When Active Directory is operating as Active Directory Domain Services (AD DS), the DC contains full NC replicas of the configuration naming context (config NC), schema naming context (schema NC), and one of the domain NCs in its forest. If the AD DS DC is a global catalog server (GC server), it contains partial NC replicas of the remaining domain NCs in its forest. For more information, see [MS-AUTHSOD] section 1.1.1.5.2 and [MS-ADTS]. When Active Directory is operating as Active Directory Lightweight Directory Services (AD LDS), several AD LDS DCs can run on one server. When Active Directory is operating as AD DS, only one AD DS DC can run on one server. However, several AD LDS DCs can coexist with one AD DS DC on one server. The AD LDS DC contains full NC replicas of the config NC and the schema NC in its forest. The domain controller is the server side of Authentication Protocol Domain Support [MS-APDS].

globally unique identifier (GUID): A term used interchangeably with universally unique identifier (UUID) in Microsoft protocol technical documents (TDs). Interchanging the usage of these terms does not imply or require a specific algorithm or mechanism to generate the value. Specifically, the use of this term does not imply or require that the algorithms described in [RFC4122] or [C706] must be used for generating the GUID. See also universally unique identifier (UUID).

little-endian: Multiple-byte values that are byte-ordered with the least significant byte stored in the memory location with the lowest address.

LM hash: A DES-based cryptographic hash of a cleartext password. See LMOWFv1, as specified in [MS-NLMP] section 3.3.1 (NTLM v1 Authentication), for a normative definition.

naming context (NC): An NC is a set of objects organized as a tree. It is referenced by a DSName. The DN of the DSName is the distinguishedName attribute of the tree root. The GUID of the DSName is the objectGUID attribute of the tree root. The security identifier (SID) of the DSName, if present, is the objectSid attribute of the tree root; for Active Directory Domain Services (AD DS), the SID is present if and only if the NC is a domain naming context (domain NC). Active Directory supports organizing several NCs into a tree structure.

NC replica: A variable containing a tree of objects whose root object is identified by some naming context (NC).

NT hash: An MD4- or MD5-based cryptographic hash of a clear text password. For more information, see [MS-NLMP] section 3.3.1 (NTOWFv1, NTLM v1 Authentication), for a normative definition.

originating update: An update that is performed to an NC replica via any protocol except replication. An originating update to an attribute or link value generates a new stamp for the attribute or link value.

primary domain controller (PDC): A domain controller (DC) designated to track changes made to the accounts of all computers on a domain. It is the only computer to receive these changes directly, and is specialized so as to ensure consistency and to eliminate the potential for conflicting entries in the Active Directory database. A domain has only one PDC.

read-only domain controller (RODC): A domain controller (DC) that does not accept originating updates. Additionally, an RODC does not perform outbound replication. An RODC cannot be the primary domain controller (PDC) for its domain.

relative identifier (RID): The last item in the series of SubAuthority values in a security identifier (SID) [SIDD]. It distinguishes one account or group from all other accounts and groups in the domain. No two accounts or groups in any domain share the same RID.

requestor: The computer that sends the request messages that are defined by this protocol.

responder: The computer that responds to request messages.

security identifier (SID): An identifier for security principals that is used to identify an account or a group. Conceptually, the SID is composed of an account authority portion (typically a domain) and a smaller integer representing an identity relative to the account authority, termed the relative identifier (RID). The SID format is specified in [MS-DTYP] section 2.4.2; a string representation of SIDs is specified in [MS-DTYP] section 2.4.2 and [MS-AZOD] section 1.1.1.2.

writable naming context (NC) replica: A naming context (NC) replica that accepts originating updates. A writable NC replica is always full, but a full NC replica is not always writable. Partial replicas are not writable. See also read-only full NC replica.

MAY, SHOULD, MUST, SHOULD NOT, MUST NOT: These terms (in all caps) are used as defined in [RFC2119]. All statements of optional behavior use either MAY, SHOULD, or SHOULD NOT.