Home > Articles > Home & Office Computing > Microsoft Windows Desktop

Describing Active Directory Components

  • Print
  • + Share This
Examine some of the most critical components in Active Directory, as well as Microsoft's recommendations for their use.
This sample chapter is excerpted from Understanding and Designing Your Active Directory Infrastructure, by Neall Alcott.
This chapter is from the book

There are many components that make up Active Directory, and it is critical that you understand these components and the concepts surrounding them. In later chapters, you will learn how and why to create these components.

This chapter describes some of the most critical components in Active Directory, as well as Microsoft's recommendations for their use. These components need to be thought out beforehand, as they can have a serious impact on the function and performance of your Active Directory. Some of these components include

  • DNS and the domain namespace
  • Domains
  • Forests
  • Trees
  • Sites

Domain Namespace

Active Directory in Windows 2000 utilizes the Domain Naming Service (DNS) standard for naming objects.

All hosts on a TCP/IP-based network must have a valid and unique IP address. An IP address is a 32-bit binary number. It is represented using dotted decimal notation, such as 192.168.0.1. As you can imagine, most humans cannot remember many IP addresses.

DNS was implemented to make the TCP/IP networking world more user friendly. DNS allows user-friendly names to be mapped to IP addresses. For example, instead of trying to remember 192.168.0.1, a DNS mapping (known as a resource record) could be created stating that COMPUTER1 maps to 192.168.0.1. The user only needs to know about COMPUTER1, not 192.168.0.1.

Another benefit of DNS is that IP addresses can and do change. The IP address of COMPUTER1 could change to 192.168.0.37. In this case, the DNS record for COMPUTER1 would be updated from 192.168.0.1 to 192.168.0.37. The users and applications would still be looking for the host name COMPUTER1 and thus would not need to be notified of the change.

DNS is a hierarchical naming system and a distributed database. As you can see in Figure 3.1, DNS looks much like an inverted tree. The root of the tree (aptly named "root") is represented by a period. The root signifies the beginning of the domain namespace. A domain namespace, in either Active Directory or DNS, defines an area with boundaries in which any object contained within must adhere to the domain-naming standard. Objects or hosts that do not adhere to the domain-naming standard will not be considered to be part of the domain namespace. As a result, they might not be able to properly access information provided by DNS. For example, when clients attempt to access Active Directory to perform logons or look up directory information, they use their domain name to determine their location within Active Directory. If they are misconfigured, the operation will fail.

Domains are branches off of the root. Figure 3.1 represents the Internet Domain Namespace, where directories below the root are the main Internet categories, such as COM, NET, and ORG. Domains can contain hosts, such as computers and servers, and also subdomains. On the Internet, these subdomains are companies and organizations, such as microsoft.com, compaq.com, npr.org, and pbs.org.

Figure 3.1 The Internet domain namespace.

The Active Directory domain hierarchy uses the same rules and procedures as DNS to resolve domain and computer names.

For example, an organization named Help and Learn, Inc. is beginning to plan its implementation of Active Directory. They have two regional divisions in their organization, called East (representing the East Coast of the United States) and West (representing the West Coast). Their plan calls for the use of helpandlearn.com as their domain namespace. All objects within Help and Learn, Inc.'s Active Directory structure would be within this namespace. The East and West regions could be implemented as subdomains in Active Directory. They would be named east.helpandlearn.com and west.helpandlearn.com. A computer object named LAPTOP1 located in the east subdomain would have the Active Directory name laptop1.east.helpandlearn.com.

Possible DNS Names

There are two very important rules when it comes to naming objects in DNS:

  • A child domain can have only one parent domain. For example: If the domain public is a child of microsoft.com, it cannot be a child of msn.com. Looking at the FQDN of the domain, it becomes apparent: public.microsoft.com is not the same domain as public.msn.com.

  • Two children of the same parent must have different names. For example: If two domains are created under the same parent domain, their names must be different due to the hierarchical DNS structure. Look at the following FQDNs: public.microsoft.com and private.microsoft.com. You cannot rename the private domain to public because public already exists.

A DNS name consists of different portions separated by periods (.). Each portion represents a domain or subdomain in the namespace. This is known as an FQDN (fully qualified domain name).

As in the previous example, a computer named LAPTOP1 in the East subdomain of Help and Learn, Inc. would have a fully qualified domain name (FQDN) of laptop1.east. helpandlearn.com.

Reading an FQDN from right to left, one can understand the DNS hierarchy. com is the root domain; helpandlearn is a subdomain of com; east is a subdomain of helpandlearn, and so on. Each domain and subdomain in the hierarchy contains its own portion of the DNS namespace.

A host's name can also be resolved by using its relative name. The relative name is simply the host name without the DNS hierarchy. To resolve a relative host name, the requester must be located in the same domain.

Back to the example, LAPTOP1 is the relative name of laptop1.east.helpandlearn.com. To query DNS for LAPTOP1 using its relative name only, the requester would need to be a member of the east domain.

Internal Versus External Namespace

If an organization that is implementing Active Directory requires Internet connectivity, the organization would need to register their root domain name with one of the Internet naming registrars. Once a unique domain name is registered (and thus a DNS namespace created), the Active Directory namespace is implemented as one or more subdomains of the Internet root domain (see Figure 3.2).

Figure 3.2 Utilizing an external namespace.

If an organization does not require Internet connectivity, the organization can opt to utilize an internal DNS namespace. But it must be noted that Active Directory does require DNS. Active Directory uses DNS to locate servers and services within the directory. If the organization opts for an internal DNS namespace, they must still design and install the internal DNS infrastructure, including servers, domains, and so on (see Figure 3.3). It is also strongly recommended that the organization still registers its internal and external domain namespace in case of future changes.

Figure 3.3 Utilizing an internal namespace.

Overcoming Name Limitations

One of the most difficult tasks faced by an organization looking to register an Internet domain name is name availability. Many names have been registered and it may really take some creativity to find the name you want or a name that even makes sense.

An organization can register their domain name themselves or through their Internet Service Provider (ISP). If they are registering the domain name themselves, they can use one of several Internet registrars, such as Network Solutions (http://www.networksolutions.com). Network Solutions provides a simple Web-based form where you can enter the desired domain name. It will search the database to determine whether the domain name is available. If it is, you can proceed to register the name. If it is not, you will be presented with a number of optional domain names (see Figure 3.4).

Of course an organization should also consult its legal department to verify that the domain name is not infringing on any other copyrights or trademarks.

Figure 3.4 Registering a domain name using Network Solutions.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020