This lesson examines the WINS and DHCP services in Windows NT to plan for TCP/IP-based services in the Windows 2000 environment.
After this lesson, you will be able to
Estimated lesson time: 70 minutes
When planning to use Active Directory, you must understand the Transmission Control Protocol/Internet Protocol (TCP/IP) suite of protocols. TCP/IP protocols and services such as DHCP, DNS, and WINS allow users to access and use the network. During an in-place upgrade, these services should be running in parallel on another system while your server is being upgraded. If a pristine restructure is to take place, you'll need to avoid any IP address overlap and have enough IP addresses available for the parallel systems.
Windows 2000 sites are configured on the assumption of well-connected areas, which depends on how you subnet TCP/IP. Therefore, wherever possible, do not split a subnet across a slow WAN link.
You can assess your TCP/IP topology in a variety of ways:
Windows NT 4.0 DHCP services can work with any Microsoft Windows clients configured for dynamic IP address assignments. These clients include Windows 2000, Windows NT, Windows Millennium Edition (Me), Windows 9.x, and Windows 3.x systems. Before migrating a DHCP server, ensure that sufficient alternative DHCP systems exist that can renew and lease IP addresses to clients. If you don't take this step, clients might be unable to connect to the network while the DHCP server is being migrated.
To create an alternative DHCP service, you need to determine the number of clients, the lease period, the subnets being serviced, and any scope options being assigned, such as WINS address, WINS Node type, DNS address, and default gateways. You can gather this information from DHCP Manager or from the Dhcpcmd.exe utility in the Microsoft Windows NT Server Resource Kit.
However you migrate to the Windows 2000 DHCP service, you'll need to define a member of the Enterprise Admins group who will authorize the server in Active Directory; otherwise, the DHCP server will be unable to work. This is an intentional safeguard designed to prevent rogue or unauthorized DHCP servers from assigning unapproved or potentially catastrophic TCP/IP addresses.
NetBIOS (Network Basic Input/Output System) is a legacy protocol responsible for naming computers and domains across a network. It was originally designed about 1984 when PC networks consisted of only two or three machines sharing perhaps a 10-MB hard disk. For one computer to locate another computer or network service, the computer would make a broadcast for a NetBIOS name. One of the great leaps for Microsoft Windows 2000 is to make the operating system independent of NetBIOS. However, many of your legacy clients and applications might still depend on NetBIOS. Assessing NetBIOS services still in use in your enterprise and removing those not needed can substantially reduce your network traffic.
Windows NT's solution to reduce NetBIOS broadcasts is the Windows Internet Naming Service (WINS). This service resolves computer names to their IP addresses. If WINS can also be removed from the network, the burden on the network will be further reduced. Some indications of whether or not to retain WINS include the following:
You need to ascertain whether losing a WINS server will significantly affect business operations. If it will have an impact on business then you might need to schedule the WINS migration in a relatively quiet period of the business. Assess your WINS services for the following:
This practice contains two exercises that allow you to investigate DHCP and WINS. In order to complete them, you will first have to install both DHCP and WINS. Once installed, you will configure a DHCP client and test connectivity with the server. You will also gather information about the DHCP service's performance and investigate whether your network is carrying NETBIOS and WINS traffic.
In this practice, you'll look at the various components of your DHCP server. To do this, you must first install the DHCP service.
To install the DHCP service on a Windows NT Server primary domain controller
The location of your Windows NT Server installation files is requested.
The DHCP service will install.
After restarting the system, reinstall your current service pack so that the DHCP service files will be up-to-date. To do this, as you were instructed in "Getting Started", double-click the Sp5i386.exe file in the Tools folder to run the Service Pack 5 installation program.
Once the DHCP service and the service pack have been installed, you will need to configure DHCP.
To configure the DHCP service
The DHCP Manager screen appears.
The Create Scope dialog box will appear.
Figure 4.3 Create Scope dialog box
A dialog box appears, asking whether you want to activate the scope you just created.
To create extra settings to assign to clients when they log on
Figure 4.4 DHCP Options: Scope dialog box
Figure 4.5 IP Address Array Editor dialog box
A warning dialog box appears.
A byte field appears in the lower portion of the dialog box.
Your final DHCP screen should match the one shown in Figure 4.6.
Figure 4.6 DHCP Manager with a scope defined and activated
If the right pane doesn't update but remains blank, you might need to close and re-open DHCP Manager to force it to refresh.
Finally a DHCP client is required. Use MIGKIT2 for the DHCP client in these exercises, but remember it's not recommended that you use a BDC as a DHCP client in a company or other working environment.
To configure the DHCP client
If everything has been installed correctly, you should see that DHCP is enabled and an IP address has been assigned to the client computer.
In the next procedure, the Dhcpcmd utility, included with the Microsoft Windows NT Server Resource Kit, is used to obtain statistics about your DHCP service. The structure of the Dhcpcmd command is: Dhcpcmd server_IP_address command [command options]. Perform these steps from MIGKIT1.
To use the Dhcpcmd command-line utility
You should now see a client. Notice how no facility exists to print or obtain reports on your DHCP server's statistics.
dhcpcmd 192.168.0.100 serverconfig dhcpcmd 192.168.0.100 mibcounts
What results did you get?
dhcpcmd 192.168.0.100 enumclients 192.168.0.0 _h >dhcprpt.txt
dhcpcmd 192.168.0.100 enumclients 192.168.0.0 -v >dhcprpt.txt
The Dhcpcmd utility is useful for providing reports on the current state of the DHCP service and its clients, and it has three more command-line options that aren't covered here. The main reason for assessing your DHCP services is to help ascertain the following:
Chapter 12, "Business Continuity," will show some techniques to keep your DHCP services fixed until the DHCP service migration has been completed.
In this exercise, you install WINS and then assess your network for WINS and NetBIOS traffic.
To install WINS
You will be prompted to restart the system.
After restarting the system, reinstall your current service pack so that the WINS service files will be up-to-date.
To assess the WINS and NetBIOS traffic on your network
Figure 4.7 Add To Chart dialog box with three counters selected
Notice how a small blip appears in the graph as MIGKIT2 starts. This means that the WINS service is running.
Table 4.1 describes the three Performance Monitor counters and how they can be used to determine whether NetBIOS is required.
Table 4.1 Performance Monitor Counters Useful for Evaluating NetBIOS Requirements
|Queries/sec||The rate at which WINS receives NetBIOS queries||Any value greater than zero means that a client is using the WINS service to resolve NetBIOS names. If this value is comparatively low, locate the systems requiring WINS and see whether they can use DNS or another method for NetBIOS name resolution.|
|Successful queries/sec||The rate at which the WINS server successfully matches a NetBIOS name to an IP address||If this value is zero and the Queries/sec value is zero, consider removing WINS because no name resolution is taking place via WINS. |
Also perform further investigation on NetBIOS. You might also be able to remove NetBIOS provided that no NetBIOS resolution is taking place via broadcasts or an LMHOSTS file. If the Queries/sec value is high and the Successful queries/sec value is low or zero, a problem might exist with the WINS service.
|Total number of registrations/sec||The total number of registrations received by the WINS server per second||If this value is zero, no clients are making use of the WINS service and you can eliminate the WINS service in the new Windows 2000 infrastructure.|
As an alternative to using Performance Monitor, you can check the number of WINS registrations by accessing the WINS Manager from the Administrative Tools folder and viewing the number of registrations and successfully resolved queries, as show in Figure 4.8.
Figure 4.8 Viewing the activity of the WINS service in WINS Manager
In this lesson, you learned to plan to maintain backup DHCP services during the migration project. You set up and analyzed a DHCP server and created a report to help you plan migrating the service later. You studied how to maintain your WINS service during a migration. Finally you checked for NetBIOS network traffic to see whether you can safely remove such NetBIOS services as WINS and thereby improve network performance.