Glossary of Terms

The Glossary explains many of the more advanced and unusual concepts involved with truly effective Active Directory design and management as well as defining the essential building blocks.


Here is a list of terms that we define – simply click on an expression to navigate to the text:

Any explanation you need that you can’t find in the glossary? – Contact us and we’ll post and updated entry!

Active Directory Architecture

Active Directory Architecture - a distinction between Physical and Logical

The Physical is that part of the Architecture that offers availability of directory services and replication of directory data.

The Logical is that part of the Architecture that allows the Active Directory to Increase Security and ROI of the whole Windows Infrastructure.

The “Physical” is usually completed successfully because any failure is instantly visible, for example:

  • Users can’t log on properly
  • Email delivery fails

The “Logical” commonly receives less attention (time and cost constraints, specialist resource availability etc) than the Physical, but its lack of completion goes un-noticed until a critical security, DR or Audit event occurs. Some of the indicators of an incomplete Logical phase (an “under-optimised” Active Directory) are:

  • Limited implementation of strong security such as role-based authority
  • Incomplete change control enforcement
  • Compromised security audit trails
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Active Directory Optimisation

Optimisation is the process of changing the Logical architecture of an Active Directory implementation to increase its security and ROI. Physical architecture is rarely affected.

In all cases this optimisation requires that existing structure is replaced by new. There are two ways to effect this change:

The Traditional approach is to generate the new structures by iterative re-developments of the existing architecture, often utilising specialist consultancy. This approach is time consuming, expensive and intrusive. The process itself has deterred many organisations from optimisation. A new alternative is now available using the Genesis Exert System which quickly, easily and cost effectively optimises the Active Directory with little or no disruption to the business

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Hierarchical Authority

Hierarchal Authority is a description of the way that IT Administrative power is organised within an organisation. The aim is to ensure that those in possession of greater authority delegate reduced authority to those below them in such a way that individuals of ‘lesser authorities’ cannot interfere with the management of their peers.

Consider the way that operational authority is structured in most organisations:

Senior management layer:
At the Apex of any organisational hierarchy are the very few individuals that have broad and far reaching powers. These individuals should have a deeper understanding of the organisation and be fully aware of the effects that wielding their powers will have. Senior managers will usually have a broad remit of responsibility.

For example: The Finance Director takes responsibility for all aspect of financial management, and has the power to transfer any amount of money from the company accounts to pay the company bills. This authority can be delegated as the Finance Director sees fit. This breakdown and delineation of actual power is called “Role-based Authority”.

The Middle Management Layer:
The middle managers are employed by the senior management to take responsibility for a particular aspect of the running of the company. They receive their (delegated) authority from their senior manager.

For example: In the finance department, the Director hires three managers. Each will take responsibility for one of the key functions: Invoicing, Purchasing, and Reporting. To each is delegated the power required to discharge their role, for example the purchasing manager can sign of payments of up to £5000. This is role based authority again…

Critically only the Finance Director can hire & fire individuals within the Finance Department, or delegate authority to an individual in the Finance Department. The Sales Director, who is a peer director, is not authorised to perform either of these tasks within the Finance Department.

The Workforce:
The Workers are those employed by the middle managers to perform certain tasks. Typically they are only given enough authority to enable them to perform their designated tasks.

For example: In the finance department, the purchasing manger Hires ten purchasing clerks who are responsible for tabulating received invoices and preparing them for payment. But they must still get the signature of the Manager (or the Director if the Manager is away) to enact the payment. Role based authority once again…

Critically only the Purchasing Manager (or his line manager - the Finance Director) can hire & fire individuals within the Purchasing Department, or delegate authority to an individual in the Purchasing Department. The Invoicing Manager, who is a peer manager, is not authorised to perform either of these tasks within the Purchasing Department.

The following diagram is a representation of how a network Authority Structure may look within a company with International offices:

Rules:

  • “Enterprise Admin” can create a “Domain Admin”
  • Only an “Enterprise Admin” or ”Domain Admin” can create a “Paris Admin” or “London Admin”
  • Only an “Enterprise Admin” or “Domain Admin” or ”London Admin” can create a “London Server Admin”
    Note: A “Paris Admin” cannot perform any of these tasks
  • The Security Administrators have their own authority chain that is ‘external’ to the main authority stream – this is an operational over-ride facility.
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Privilege Elevation

Privilege Elevation is the goal of any many attacks against computer systems. The aim is to find a way of obtaining authority greater than was originally assigned, for example:

  • A normal user trying to gain Admin powers over his workstation
  • An email administrator trying to get control over the SQL databases
  • A user administrator trying to reset a domain administrator’s password
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Expert System

An Expert system is a computer system encoded with some of the expertise of a human professional. Ideally it has a relatively simple interface, allowing a user with limited understanding to step through a complex process, then combine the users input with its in-build knowledge to produce a useful result that the user would not have been able to create alone, for example:

  • A program that asks you a series of questions and from your answers writes your will is an expert system designed to reduce your reliance on lawyers.
  • A computer that recognises patterns of data flowing across you network and alerts you to potential issues is an expert system designed to help a network manager or security specialist work more efficiently.

Genesis is an expert system designed to allow organisations to dramatically reduce the time and cost requirement of Active Directory™ implementation.

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Role Based Privileges

This is where a user or administrator is granted only those privileges that enable them to discharge their duties.

For example: a member of the support team may need to add users, but they don’t need to create computer accounts in the Active Directory (let’s say that that task is handled by the “Network Team”), so granting them the privilege to create computer accounts is an unnecessary risk to they infrastructure.

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Role Separation

Role separation is the principle that administrative roles should be separated. For example: London User Admins, Birmingham User Admins. Administrative authorities, and their responsibilities, should be assigned to different network user credentials. It may be that one individual has several different sets of credentials to cover all aspects of their duties.

For example:

  • An administrator would be able to perform most of his duties using normal user credentials - sending email, writing documents, and so on. But when they need to, say, add a new user, they would log on with different credentials - credentials that would carry sufficient privileges to carry out this task. When the task has been completed they would log out and return to their normal duties using normal credentials.
  • The authority of a Domain Admin account is not required for 98% of normal operational work. This authority is very high level Administrator authority and should not be invoked (logged on with…) unless it is needed. Though sometimes impractical, it is better practice for the administrator who is assigned a Domain Admin account to also be assigned a lesser admin account with which to perform tasks that do not need such very high level Administrator authority as Domain Admins.

Correct implementation of Role Separation minimises the potential of administrative mistakes and lessens the chance of a third party gaining access to system resources if the administrator is not present at the terminal upon which they were working.

Although very simple, Role Separation is often overlooked as a basic security measure.

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Organisational Units

An object in the Active directory Database that is used to “contain” other objects (especially the objects that are used to represent Users and Computers). OUs allow objects to be “grouped” in the container so that various security and management functions can be applied to them.

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Organisational Unit (OU) Architecture

The OU architecture is the collection of OUs (and how they are interlinked) that is devised to hold, and differentiate between the objects that represent the users (normal and administrative), computers (servers, workstations, laptops etc), printers etc.

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Group Policy

Active Directory objects that are used to apply policy to groups of computers and/or users contained within Active Directory containers. The type of policy includes not only registry-based policy found in Windows NT Server 4.0, but is enabled by Directory Services to store many types of policy data, for example:

  • file deployment
  • application deployment
  • logon/logoff scripts
  • startup/shutdown scripts
  • domain security
  • Internet Protocol security (IPSec), and so on.

The collections of policies are referred to as Group Policy objects (GPOs).

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Group Policy Architecture

Group Policy Architecture is the layout of Group policy objects, their interaction, security control and linkage with the active directory that determines what policy will affect any given user when sitting at any given machine. It is the complex aspect of Group Policy implementation.

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ROI: Return On Investment

The financial return an investment will generate. A measure used in marketing or cost justification. E.g. The installation will cost £10K, but will cut Admin costs by £1k per month, giving full return on investment in 10 months.

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TCO: Total Cost of Ownership

The cost to maintain a system or a piece of software over time. E.g. A workstation costs £2000 per year in support staff time and part replacement.

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GUID: Globally Unique Identifier

A Globally Unique Identifier or GUID is a pseudo-random number used in software applications. Each generated GUID is "statistically guaranteed" to be unique. This is based on the simple principle that the total number of unique keys ( or ) is so large that the possibility of the same number being generated twice is virtually zero

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  Last updated: 10/12/2009