Chapter 10, WINS in Name Resolution Designs

|1| Chapter 10 Overview

A. Designs That Include WINS

1. Learn the requirements and constraints for creating a WINS design.

2. Understand the relationship between WINS and Windows 2000.

3. Determine when it’s appropriate to use WINS in name resolution solutions.

4. Identify the design decisions you’ll need to make.

B. Essential WINS Design Concepts

1. Determine where to use WINS servers in your design.

2. Determine which network segments require NetBIOS name resolution.

3. Determine which network segments require WINS client proxy support.

4. Select appropriate WINS client options for your design.

5. Select appropriate methods for replicating WINS updates between WINS servers.

C. Name Resolution Protection in WINS Designs

1. Learn how to prevent unauthorized private network users from modifying the configuration of WINS servers.

2. Learn how to prevent Internet users from modifying the configuration of the WINS servers.

D. WINS Design Optimization

1. Learn how to increase the availability of your WINS design.

2. Increase the performance of your WINS design.

Chapter 10, Lesson 1

Designs That Include WINS

|2| 1. WINS and Name Resolution in Networking Services Designs

A. Most Microsoft Windows NT 4.0–based networks run on TCP/IP and use NetBIOS names and WINS to access resources.

B. WINS is one way to provide NetBIOS over TCP/IP (NetBT) name resolution.

C. You can also provide NetBIOS name resolution by using

1. A HOSTS file on the local computer

2. An LMHOSTS file on the local computer or on shared computers

3. b-Node Broadcasts

4. Domain Name System (DNS)

D. WINS is the only name resolution method that provides centralized administration and support for the following:

1. NetBIOS name types (such as NetBIOS groups)

2. NetBIOS name registration and resolution

E. This chapter focuses on WINS for NetBIOS name resolution.

|3| 2. WINS and Windows 2000

A. WINS is an industry-standard protocol that provides

1. Name registration: WINS servers receive NetBIOS name registration requests from WINS clients and place the NetBIOS names in the WINS database

2. Name resolution: WINS servers receive NetBIOS names and return the corresponding IP addresses

3. Name release: WINS clients notify the WINS server that they are shutting down

B. Windows 2000 includes WINS Client, WINS Proxy, and WINS Server services.

1. WINS Client

a. Is the NetBT portion of the IP stack in Windows 2000

b. Receives requests for NetBIOS name resolution from local applications

c. Forwards those requests to WINS servers

d. Allows for selection of the NetBT WINS node type for each WINS client

(1) b-node: resolves NetBIOS names by sending IP broadcasts on the local network segment

(2) p-node: resolves NetBIOS names by sending IP unicast traffic to a NetBIOS names server

(3) m-node: resolves NetBIOS names by attempting to use b-node to resolve NetBIOS names first. If unsuccessful, uses p-node instead.

(4) h-node: resolves NetBIOS names by attempting to use p-node, or b-node alternatively

e. Other operating systems also include WINS clients.

2. WINS Proxy

a. Necessary for providing WINS NetBIOS name registration and resolution for non-WINS clients

b. WINS Client receives the requests from non-WINS clients that run on the same network segment, and then forwards the requests to WINS servers.

3. WINS Server

a. A service that runs on Windows 2000

b. Provides NetBIOS registration, resolution, and release to WINS clients

c. Uses the IP stack in Windows 2000 to communicate with WINS clients, other WINS servers, DNS servers, and DHCP servers

d. You need to specify a fixed IP address for all network interfaces on the WINS server that communicate with the WINS Server service.

e. Manages a locally stored database containing the WINS records for name resolution that are resolved by the WINS server

f. Availability:

(1) WINS Server service is available in Microsoft Windows 2000 Server, Microsoft Windows 2000 Advanced Server, and Microsoft Windows 2000 Datacenter Server.

(2) WINS Server service is not available in Microsoft Windows 2000 Professional.

C. To create WINS designs, you should understand the following:

1. Common TCP/IP configuration parameters, including

a. IP addresses

b. Subnet masks

c. Default gateways

2. IP routed networks, including

a. Subnets

b. Network segments

c. Routers

d. IP switches

3. How to use NetBIOS in a network, including

a. Naming conventions

b. Name registration

c. Name resolution

d. Name release

4. NetBIOS name resolution methods, including

a. IP packet broadcasts

b. LMHOSTS files

c. HOST files

d. WINS name servers

5. DNS name resolution methods, if relevant for your design

6. Common NetBIOS name types and how to use them in WINS resolution

|4| 3. WINS Design Requirements and Constraints

A. You must collect design requirements and constraints before creating your design.

B. Make design decisions based on those requirements and constraints, including

1. The amount of data transmitted between existing network segments that contain the WINS clients and WINS server

2. Which network segments require NetBIOS name resolution

3. WAN connections in use

4. Plans for network growth

a. Number of NetBIOS-based computer resource records in existing network databases

b. WINS server placement

b. Operating systems running NetBIOS

|5| 4. WINS Design Decisions

A. Apply the information you collected regarding your organization’s requirements and constraints to make WINS design decisions.

B. You need to make the following decisions:

1. How to integrate WINS into the existing network, based on

a. Existing desktop operating systems

b. Existing WINS servers

c. Existing routed network segments

2. How to ensure that NetBIOS name resolution is always available to network users

3. How to optimize network traffic between NetBIOS clients and NetBIOS servers

|6| 5. WINS and Microsoft Network Designs

A. WINS is necessary in your Windows 2000 design if any of the following are true:

1. Users are running Microsoft operating systems prior to Windows 2000 that require authentication in Active Directory directory service.

a. Earlier Microsoft operating systems use the LAN Manager authentication method.

b. LAN Manager relies on NetBIOS.

2. The IP-routed network segments require NetBIOS name support.

a. Non-routed network segments can use b-node broadcasts to resolve NetBIOS names, but IP-routed network segments cannot.

b. WINS uses unicast IP packets to resolve NetBIOS names.

3. Your network’s client/server applications require NetBIOS for communications.

4. Users are using file services or print services from Microsoft operating systems prior to Windows 2000.

B. If your design includes Microsoft networking and routed IP networks, ensure that domain controllers, member servers, application servers, and client computers can resolve IP addresses for NetBIOS names stored in WINS.

|7| 6. Windows 2000 Without NetBT and WINS

A. You don't need WINS if your organization uses Windows 2000 exclusively.

1. Earlier versions of Microsoft operating systems require NetBIOS, which means they also require NetBT and WINS.

2. Windows 2000 provides all of the following without relying on NetBIOS:

a. File services

b. Print services

c. Application services

d. Authentication

B. You can remove NetBT from all computers and eliminate the need for WINS if all of the following are true:

1. All computers using file and print services in your network are using Windows 2000.

2. Applications that run on the network do not require NetBIOS.

3. Network users are authenticated by Windows 2000 and Active Directory.

Chapter 10, Lesson 2

Essential WINS Design Concepts

|8| 1. Determining Which Segments Require NetBIOS Name Resolution

A. You need to provide NetBIOS name resolution for all network segments that include the following:

1. File servers, print servers, or application servers that use NetBIOS to communicate

2. Desktop computers that access the file servers, print servers, or applications that use NetBIOS to communicate

B. NetBIOS name resolution is not typically required for Internet users because they are more likely to access resources using one of the following methods:

1. Client/server protocols

2. Peer-to-peer protocols

|9| 2. Selecting WINS Client Proxy Support

A. WINS proxies allow non-WINS clients to use WINS servers to resolve NetBIOS names.

B. A WINS Proxy is a component of the WINS Client.

C. The name resolution process is as follows:

1. Non-WINS clients use b-node broadcasts to resolve NetBIOS names.

2. The WINS client on the same network segment receives the b-node broadcasts and forwards non-WINS client requests to the WINS server.

3. The WINS server resolves the request and returns the IP address to the WINS client.

4. The WINS client returns the response to the non-WINS client as a b-node broadcast reply.

D. Network segments that require NetBIOS name resolution may include:

1. WINS clients only, in which case no WINS proxies are required

2. All non-WINS clients, in which case

a. WINS proxies are required

b. At least one WINS client must be included on the network segment to provide communications with the WINS server

3. A combination of WINS and non-WINS clients, in which case

a. WINS proxies are required

b. At least one of the WINS clients must be designated as the WINS proxy for the non-WINS clients

|10| 3. Selecting WINS Client Options

A. WINS Client options determine how WINS clients resolve NetBIOS names.

1. Sequence of WINS servers

2. WINS node type

3. LMHOSTS lookup

4. HOSTS lookup

5. DNS lookup

B. Sequence of WINS servers

1. You can specify multiple WINS servers that are available to WINS clients for NetBIOS name registration and resolution.

2. The order in which WINS servers are listed determines the order in which WINS clients attempt to contact them.

3. If the first listed WINS server is unavailable, the WINS client tries the next listed WINS server.

4. The process continues until the WINS client makes contact with a WINS server or the list of WINS servers is exhausted.

5. You can change the sequence of WINS servers to provide load balancing of WINS queries across multiple WINS servers.

C. WINS node type

1. Specifies the NetBT WINS node type for each WINS client

2. Available node types are

a. b-node

b. p-node

c. h-node

d. m-node

3. b-node

a. Resolves NetBIOS names by sending IP broadcasts on the local network segment

b. These broadcasts are not usually forwarded across IP routed network segments unless routers are specifically configured to route broadcast packets.

4. p-node

a. Resolves NetBIOS names by sending unicast traffic to the WINS server

b. Appropriate for IP-routed network segments

5. h-node

a. Attempts to use p-node to resolve NetBIOS names first

b. If p-node fails, the WINS client attempts to use b-node.

c. Use h-node when most of the NetBIOS names to resolve are on other network segments.

6. m-node

a. Attempts to use b-node to resolve NetBIOS names first

b. If b-node fails, the WINS client attempts to use p-node.

c. Use m-node when most of the NetBIOS names to resolve are on the local network segment.

D. LMHOSTS lookup

1. Specifies that the WINS client can use the LMHOSTS file to resolve NetBIOS names

2. Not usually included in WINS designs

3. Include if you want to create manual entries for NetBIOS resources that are not registered and are not appropriate to enter manually in WINS

E. HOSTS lookup

1. When b-node and p-node NetBIOS name resolution are unsuccessful, the WINS client attempts to resolve the NetBIOS name by using the HOSTS file.

2. The WINS client always uses the HOSTS file (unlike the LMHOSTS file, which is often disabled).

3. The HOSTS file does not include the extended NetBIOS information that is included in the LMHOSTS file.

F. DNS lookup

1. Specifies that the WINS client can use DNS to resolve NetBIOS names if p-node and b-node attempts fail

2. Can be enabled or disabled on each WINS client

|11| 4. Determining WINS Server Placement

Note The ultimate goal of properly placing WINS servers is to provide the best client performance while reducing router traffic.

A. You need to decide where to place WINS servers so that WINS clients can resolve NetBIOS names.

B. Each WINS server can support up to 10,000 WINS clients.

|12| C. Depending on your organization’s needs, you may want to use multiple WINS servers.

1. To reduce or eliminate WINS traffic between locations, place at least one WINS server at each location.

2. To reduce or eliminate WINS traffic between network segments at a single location include multiple WINS servers at that location.

|13| 5. Selecting WINS Replication Methods

Note When you have multiple WINS servers in a network design, you need to plan for replication to synchronize the databases. Determining the maximum convergence time is a critical part of designing the replication strategy.

A. For multiple WINS servers, you need to replicate the WINS database on each WINS server to the other WINS servers.

1. Replication is necessary so that each WINS server contains a full list of all WINS clients.

2. Convergence time

a. Convergence is the length of time taken before changes in one WINS server’s database are replicated at other WINS servers.

b. Convergence time must be determined in your design for all WINS servers.

B. You can control the convergence time by

1. Modifying the WINS replication topology

2. Calculating the maximum convergence time

3. Specifying replication partner type

C. WINS replication topology

1. Defines the logical replication connections between all WINS servers

|14| 2. The hub-and-spoke model is the most commonly used.

Note The hub-and-spoke model is Microsoft’s recommended configuration because it provides the shortest convergence times.

a. Most effective for reducing convergence time

b. A centralized WINS server (the hub) replicates to all other WINS servers (the spokes).

3. You can extend the hub-and-spoke model for larger organizations.

a. Designate multiple hubs, by location or region.

b. Other WINS servers at that location are spokes to the local hub WINS server.

c. Designate one WINS server as the hub for the entire organization; the local hubs are spokes to that main hub.

|15| D. Calculating WINS maximum convergence time

1. Determine the acceptable length of time between these events:

a. When the NetBIOS name is registered on any WINS server

b. When WINS clients can resolve that NetBIOS name from any WINS server

2. Determine the maximum convergence time by reviewing

a. How often users access resources in other locations, and at what speeds

b. How often resources are added to or removed from the network

3. Determine the replication schedule, in hours, between all WINS servers.

a. In hub-and-spoke designs, determine the replication schedule between the hub WINS server and each spoke WINS server.

b. In other designs, determine the replication schedule between all possible replication paths.

c. In any design, assume that a WINS update occurred immediately after the last WINS replication.

4. Total the number of hours the replication process will take between all possible combinations of WINS servers.

a. Examine all possible replication paths.

b. Account for the replication time required for any intermediary WINS servers in your design.

5. Identify the longest replication time required between any two WINS servers.

6. The result is the convergence time for your design.

|16| E. WINS replication partner type

1. After specifying the maximum convergence time, you need to specify the WINS replication partner type to control the convergence time.

2. You can specify that each WINS server replicate to other WINS servers by using one of these methods:

a. Pull partner replication

b. Push partner replication

c. Push/pull partner replication

3. Pull partner replication

a. A WINS server requests (or pulls) updates from other WINS servers at scheduled intervals.

b. Use this method for WINS servers in separate locations when network segments between WINS servers have limited data rates or network traffic capacity.

c. Advantage: adjustable; you can reduce network utilization if necessary

d. Disadvantage: requires more convergence time

4. Push partner replication

a. A WINS server notifies other WINS servers of available updates (pushes the notification).

b. Use for WINS servers within the same location when network segments between WINS servers have high-speed data rates or high network traffic capacity.

c. Advantage: minimizes convergence time

d. Disadvantage: not adjustable

5. Push/pull partner replication

Note The push/pull and pull partner replication methods are the best methods because they minimize convergence time. The push-only method should be used only in rare cases (such as for slow WAN links).

a. A WINS server notifies other WINS servers of updates and requests updates from other WINS servers.

b. Use for WINS servers within the same location when network segments between WINS servers have high-speed data rates or high network traffic capacity.

c. Advantage: minimizes convergence time

d. Disadvantage: not adjustable

Chapter 10, Lesson 3

Name Resolution Protection in WINS Designs

|17| 1. Preventing Unauthorized User Access

A. You need to prevent unauthorized users from accessing the WINS database.

B. You can protect your WINS servers and their databases in two ways:

1. Grant only authorized network administrators the permission to manage WINS servers.

a. Create a Windows 2000 group and assign the group the permissions needed to manage your organization’s WINS servers.

b. In the Windows 2000 group, include the authorized network.

2. Isolate WINS servers from public network access.

Chapter 10, Lesson 4

WINS Design Optimization

|18| 1. Enhancing WINS Availability

A. You can optimize your design for increased availability by using the following strategies:

1. Use Windows Clustering server clusters.

a. Windows 2000 WINS Server service is cluster-aware.

b. The WINS database is stored on a shared cluster drive.

c. The WINS Server service runs on only one cluster node, called the active node, at a time.

d. If the WINS active node fails, the other cluster node automatically starts the WINS Server service.

e. The redundant cluster node has the current WINS NetBIOS name database from the failed cluster node.

2. Include multiple WINS servers with replicated WINS databases.

a. Replicate WINS database entries between multiple WINS servers.

b. Each WINS server manages a portion of the WINS clients that are registered in the database.

c. If one WINS server fails for any reason, the other WINS server can provide NetBIOS name resolution for the WINS clients.

d. Advantage: requires no additional hardware or software resources

e. Disadvantage: no automatic failover—clients may experience delays in NetBIOS name resolutions if the first WINS server fails

3. Dedicate a computer to running WINS.

|19| 2. Improving WINS Performance

A. You can optimize your design for improved performance.

B. You can use the following strategies to improve WINS configuration performance:

1. Reduce WINS query resolution time.

2. Reduce WINS replication traffic.

C. Reducing WINS query resolution time

1. Load balance WINS NetBIOS name resolution across multiple WINS servers.

a. This strategy is useful when existing WINS servers are saturated and you cannot upgrade hardware.

b. Evenly distribute WINS clients across multiple WINS servers to ensure that each WINS server manages approximately the same number of WINS clients.

2. Enable burst handling on WINS servers.

a. The WINS server can become saturated when too many WINS clients try to register their NetBIOS names at the same time.

b. When burst handling is enabled, the WINS server acknowledges simultaneous WINS registration requests that exceed a specified threshold with a varied Time to Live (TTL).

c. The WINS clients must then retry registering the NetBIOS names after the TTL expires.

d. Make the threshold low enough so that WINS servers can use burst handling before the computer’s hardware resources are exhausted and WINS registration performance degrades.

3. Dedicate a computer to WINS to prevent other applications and services from consuming system resources.

D. Reducing WINS replication traffic

Note Replication traffic can affect the performance of WAN links. The methods described below can reduce replication traffic. You can modify the replication schedule so that replication occurs during non-peak hours.

1. Specify pull partner replication.

a. Reduces replication traffic

b. Utilizes WAN network segments more efficiently

(1) WINS database updates retrieved at regular intervals

2. Change the pull partner replication interval.

a. Changing this interval also changes the convergence time.

b. Increase this interval to send more updates during one pull partner replication (and reduce traffic).

c. Decrease this interval to reduce the convergence time.

3. Specify WINS persistent connections.

a. WINS servers prior to Windows 2000 require new server connections to be established each time replication is performed.

b. In Windows 2000, the WINS service disconnects from replication partners each time the replication process is completed.

c. WINS persistent connections allow WINS servers to retain open connections with replication partners.

|20| Chapter Summary

A. WINS services in Windows 2000 resolve NetBIOS resource names to IP addresses and vice versa.

B. WINS services in Windows 2000 include

1. WINS Client

2. WINS Proxy

3. WINS Server

C. Using WINS in your design is necessary when

1. Users who run Microsoft operating systems prior to Windows 2000 require authentication in Active Directory

2. IP-routed network segments require NetBIOS name support

3. Client/server applications require NetBIOS

4. Your design includes file services or print services provided by Microsoft operating systems prior to Windows 2000

D. WINS Client options let you specify how the WINS client resolves NetBIOS names.

1. The order of WINS servers that the WINS client contacts

2. The WINS node type to use

3. Whether to use the LMHOSTS file to resolve NetBIOS names

4. How to use the HOSTS file to resolve NetBIOS names

5. Whether to use DNS to resolve NetBIOS names

E. Depending on your organization’s needs, you can use multiple WINS servers in your design and even within one location.

1. If you use multiple WINS servers, you must replicate the WINS database across WINS servers.