Home > Articles > Certification > Microsoft Certification

  • Print
  • + Share This
This chapter is from the book

This chapter is from the book

Planning a DNS Namespace Design

Plan a host name resolution strategy.

  • Plan a DNS namespace design.

Up to this point in our discussion about DNS, we have looked at only the historical and design aspects of DNS—and for good reason. Only by understanding how DNS was created and designed can you effectively plan and implement a DNS design in a Windows Server 2003 Active Directory domain. Because DNS permeates Windows Server 2003, you should deliberately and carefully plan your DNS namespace before you ever perform the first installation of Windows Server 2003 on a computer.

TIP

The following discussion about DNS assumes that you are already familiar with installing the DNS service and performing basic management and configuration tasks. If you need a review, see Chapter 2 of MCSA/MCSE 70-291 Training Guide: Implementing, Managing, and Maintaining a Windows Server 2003 Network Infrastructure, (2003, Que Publishing; ISBN: 0789729482) by Will Schmied and Dave Bixler.

The following list represents some questions you should ask yourself when planning your namespace needs:

  • Is your DNS namespace to be used for internal purposes only? If so, you can use characters that are not typically used in DNS names, such as those outside the RFC 1123 standards. An example might be bigcorp.local.

  • Is your DNS namespace to be used on the Internet as well? If you are currently using a corporate DNS namespace on the Internet, or think that you might at any point in the future, you should register your own domain name and conform to Internet naming standards.

  • Will you be implementing Active Directory? The design and implementation of Active Directory on your network play a critical role in determining how domains should be created and nested within each other.

You have the following three basic options to consider when planning the DNS namespace you will be using:

  • Use an existing DNS namespace—This option uses the same namespace for both the internal (corporate network) and external (Internet) portions of your network. If your domain name is bigcorp.com, you would use it for both internal and external use. Although this method is the easiest and provides simple access to both internal and external resources, it poses additional administrative requirements because an administrator must ensure that the appropriate records are being stored on the internal and external DNS servers as a security precaution.

  • Use a delegated DNS namespace—This option uses a delegated domain of the public namespace. If your domain name is bigcorp.com, you might consider using corp.bigcorp.com for the internal namespace. When you use this option, the corp.bigcorp.com domain becomes the root of the Active Directory forest and domain structure. Internal clients should be allowed to resolve external namespace addresses; however, external clients should not. Using a delegated DNS namespace provides a namespace that is easy to understand and remember, and that fits in nicely with the existing registered domain name. All internal domain data is isolated in the domain or domain tree, thus requiring its own DNS server for the delegated internal domain. The downside to delegated namespaces is that this adds length to the total FQDN.

  • Use a unique DNS namespace—This option uses a completely separate but related domain name for your internal namespace. As an example, if you are using bigcorp.com for your external namespace, you might use bigcorp.net for your internal namespace. This configuration provides the advantage of improving security by isolating the two namespaces from each other. Additionally, the administrative burden is relatively low because zone transfers do not need to be performed between the two namespaces, and the existing DNS namespace remains unchanged. In addition, this option prevents internal resources from being exposed directly to the Internet.

Consider the following example of a fictitious company that is in the planning stages of a major worldwide network reorganization and upgrade to Windows Server 2003 Active Directory. Gidget's Widgets, Inc., is a major manufacturer of household goods and already owns the gidgets.com domain name for its Internet Web site. Gidget's makes everything from bath towels to kitchen sinks. Gidget's corporate headquarters are located in the United States, with regional field offices in Canada, Mexico, England, Germany, India, Japan, and Australia. Gidget's corporate structure has the following major departments: Executive, Administrative, Engineering, Manufacturing, Facilities, Sales, Legal, and Information Services. Within each department are one or more individual divisions. How would you go about designing a DNS namespace for the Gidget's Widgets internal network?

You have several options; let's assume for the sake of argument that you are going to first create a delegated domain named corp to serve as the root of the internal network and also as the Active Directory root. Starting with the corp.gidgets.com domain, you could create fourth-level domains by country code. Within these domains, you could create fifth-level domains, as required, for each of the major departments. You might end up with a configuration that looks something like that shown in Figure 3.2.

Figure 3.2Figure 3.2 Gidget's network has been nicely organized by using countries as fourth-level domains and major departments as fifth-level domains.

If you were a network administrator in the United States working from a computer called GREENGUY42, your FQDN would be greenguy42.it.us.corp.gidgets.com. Of course, you could also design the DNS namespace using continents instead of countries, if desired. When creating DNS namespaces that are several levels deep like the example in Figure 3.2, you must keep in mind some general DNS restrictions as outlined in Table 3.1.

Table 3.1 DNS Name Restrictions

Restriction

Standard DNS

DNS in Windows Server 2003 (and Windows 2000)

Characters

Supports RFC 1123, which permits A to Z, a to z, 0 to 9, and the hyphen (-).

Supports several different configurations: RFC 1123 standard, as well as support for RFCs 2181 and the character set specified in RFC 2044.

FQDN length

Permits 63 bytes per label and 255 bytes for an FQDN.

Permits 63 bytes per label and 255 bytes for an FQDN. Domain controllers are limited to 155 bytes for an FQDN.


TIP

Designing the DNS hierarchy Several of the examples presented in this chapter do not represent "best design practices" in that they have many levels of depth. This is done for illustrative purposes to help you gain a better understanding of how DNS works. In reality, you may want to consider placing resources within Organizational Units instead of fifth-level domains and below. Having too many levels in your domain architecture can lead to slower authentication, among other issues.

No matter what design you settle on, you must (in most cases) get it right the first time. Redesigning a DNS namespace is a difficult and time-consuming task after the fact, at best. In addition, failing to properly design the namespace for Active Directory compatibility can lead to functionality problems in the future.

After you've planned your namespace, you're ready to get down to business and start working out the finer points of your DNS implementation. The next thing you need to plan for is the types of zones you will be using. But what exactly is a zone?

  • + 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