Home > Articles > Certification > Microsoft Certification

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

This chapter is from the book

Implementing NetBIOS Name Resolution

Plan a NetBIOS name resolution strategy.

  • Plan NetBIOS name resolution by using the LMHOSTS file.

Microsoft TCP/IP uses NetBIOS over TCP/IP (NetBT) as specified in RFC 1001 and 1002 to support the NetBIOS client and server programs in the local area network (LAN) and wide area network (WAN) environments. Before we look at the specifics of NetBIOS name resolution, let's briefly review how computers communicate on the network. This review should help you understand how the different NetBIOS modes work and why some are preferable to others.

NOTE

What's multicasting? Multicasting is the act of transmitting a message to a select group of recipients. This is in contrast to the concept of a broadcast, where traffic is sent to every host on the network, or a unicast, where the connection is a one-to-one relationship, and there is only one recipient of the data. Think about sending an email message. If you send an email message to your manager, it is an example of a unicast message. If you send an email message to every user on the system, it is a broadcast. Send an email message to a mailing list, and you have sent a multicast message, which falls between the previous two. Teleconferencing and videoconferencing use the concept of multicasting, as does broadcast audio, where the connection is one to a selected group. At this time, only a few applications take advantage of this feature, but with the growing popularity of multicast applications, you may see more multicast applications in the future. WINS is one that you can keep on the list, but only for small networks.

Computers can use two ways to communicate on a network:

  • Through broadcast messages, which every computer receives

  • Through directed messages, which are sent to a specific computer

Whenever possible, communicating through directed messages is preferable. This approach cuts down on the amount of network traffic and ensures that only the affected hosts receive the message. It also ensures that the messages propagate across routers. So, Microsoft needed to make sure that WINS communicated primarily with directed messages. The company accomplished this by allowing several types of NetBIOS naming methods. These naming methods are commonly called node types. A node is simply a device on a network. Every computer on a Microsoft computer is configured as one of four node types. The node type determines whether the computer will learn names through broadcast messages, directed messages, or some combination of broadcast and directed messages. Before you can work with WINS, you need to know what the node types are and when they are used:

  • B-node (broadcast node)—This node relies exclusively on broadcast messages and is the oldest NetBIOS name resolution mode. A host needing to resolve a name request sends a message to every host within earshot, requesting the address associated with a hostname. B-node has two shortcomings: Broadcast traffic is undesirable and becomes a significant user of network bandwidths, and TCP/IP routers don't forward broadcast messages, which restricts B-node operation to a single network segment.

  • P-node (point-to-point node)—This node relies on WINS servers for NetBIOS name resolution. Client computers register themselves with a WINS server when they come on the network. They then contact the WINS server with NetBIOS name resolution requests. WINS servers communicate using directed messages, which can cross routers, so P-node can operate on large networks. Unfortunately, if the WINS server is unavailable, or if a node isn't configured to contact a WINS server, P-node name resolution fails.

  • M-node (modified node)—This hybrid mode first attempts to resolve NetBIOS names using the B-node mechanism. If that fails, an attempt is made to use P-node name resolution. M-node was the first hybrid mode put into operation, but it has the disadvantage of favoring B-node operation, which is associated with high levels of broadcast traffic.

  • H-node (hybrid node)—This hybrid mode favors the use of WINS for NetBIOS name resolution. When a computer needs to resolve a NetBIOS name, it first attempts to use P-node resolution to resolve a name via WINS. Only if WINS resolution fails does the host resort to B-node to resolve the name via broadcasts. Because it typically results in the best network utilization, H-node is the default mode of operation for Microsoft TCP/IP client computers configured to use WINS for name resolution. Microsoft recommends leaving TCP/IP client computers in the default H-node configuration.

TIP

Global replication settings Because we just finished discussing configuring replication partners, these parameters should look familiar. However, in this section the changes apply to any replication partners created after the modifications are made. They are not applied to existing replication partners.

CAUTION

It takes two to replicate Remember that you must configure both partners in a replication relationship to replicate with each other; otherwise, replication does not occur.

TIP

Microsoft does test on backward compatibility Don't be fooled. Just because WINS is a legacy technology, that doesn't mean it won't be tested on the exam. Microsoft recognizes the importance of backward compatibility, and as a result, you can expect to see questions on WINS for this exam. If you have not worked with it in a legacy environment, make sure you understand how WINS works.

The Method WINS Uses to Resolve a Name

The time may come when you need to understand exactly how WINS resolves a name. (Because H-node is not only the default but is also the recommended configuration, we restrict our discussion to the H-node name resolution.) When a WINS client computer configured for hybrid node needs to resolve a hostname, it goes through the following series of steps:

  1. The WINS client computer checks its NetBIOS name cache. If the name is found, that name is returned.

  2. The client queries the WINS server. If the name is found, that name is returned.

  3. The client issues a broadcast to find the host on the local network. If the name is found, that name is returned.

  4. The client looks for the LMHOSTS file to check for an entry. If the name is found, that name is returned.

  5. The client looks for the HOST file to check for an entry. If the name is found, that name is returned.

  6. The client queries the DNS server for the entry. If the name is found, that name is returned.

  7. If all these methods fail, the WINS client computer issues an error message saying that it cannot communicate with the host.

TIP

Registering with WINS When your Windows client computer enters the network, it registers with WINS so that other Microsoft client computers can resolve its name to an address. For the exam, you should be aware that although a WINS proxy server can be used to resolve names for hosts that have registered with WINS, it cannot be used to register with WINS. You need access to the WINS server to successfully register.

TIP

Another point that many people have a misconception about is how clients actually contact the WINS server. Unlike DHCP clients, WINS clients cannot locate a WINS server through broadcasts. A WINS server IP address needs to be provided to a client ahead of time either though DHCP or by manual configuration.

Although networks can be organized using a mixture of node types, Microsoft recommends against doing so. B-node client computers ignore P-node directed messages, and P-node client computers ignore B-node broadcasts. Therefore, it is conceivable that two client computers could separately be established with the same NetBIOS name. If WINS is enabled on a Windows 2000 or XP computer, the system uses H-node by default. Without WINS, the system uses B-node by default. Non-WINS client computers can access WINS through a WINS proxy, which is a WINS-enabled computer that listens to name query broadcasts and then queries the WINS server on behalf of the requesting client computer.

The actual configuration of a computer to use LMHOSTS for NetBIOS name resolution is not done by using the WINS console or a Group Policy Object, as you might expect. You must actually configure it computer by computer by setting the options available to you on the WINS tab of the Advanced TCP/IP Settings dialog box, as shown in Figure 3.18.

Figure 3.18Figure 3.18 On the WINS tab of the Advanced TCP/IP Settings dialog box, you can configure the network connection to use an LMHOSTS file.

You have the following options available to you to allow the use of the LMHOSTS file on the local computer:

  • Enable LMHOSTS lookup—This option, which is selected by default, specifies that an LMHOSTS file is to be used to resolve NetBIOS hostnames to an IP address.

  • Default—This option, which is selected by default, specifies that this network connection is to obtain the NetBIOS over TCP/IP (NetBT) setting from the Windows DHCP server that granted its lease.

  • Enable NetBIOS over TCP/IP—This option specifies that this network connection is to use NetBT and WINS.

  • Disable NetBIOS over TCP/IP—This option specifies that this network connection is not to use NetBT and WINS.

LMHOSTS files typically contain entries similar to the following ones, which are examples given the default LMHOSTS file located in the %systemroot%\System32\Drivers\Etc folder:

102.54.94.97   rhino
102.54.94.123  popular
102.54.94.117  localsrv

Each entry maps a NetBIOS name to an IP address for hosts that are not located on the local subnet, thus allowing legacy clients to locate other legacy clients on the network.

  • + 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