In this lesson, you'll look at the importance of DNS to the restructure process.
After this lesson, you will be able to
Estimated lesson time: 35 minutes
As you've seen in Chapter 4, "Assessing Your Network Infrastructure," the Domain Name System (DNS) performs the mapping of fully qualified domain names (FQDNs) to IP addresses. Windows 2000 and Active Directory use DNS to locate resources. When performing a restructure migration, remember the following:
It is essential that you have already thought through how you will locate resources via DNS. For example, when moving computers to the pristine environment, some of your options are the following:
Whether you decide to use any of these options, if you don't carefully plan for implementing Windows 2000 DNS, you might find that users can no longer access resources located on restructured servers.
NOTE
This book has revisited DNS on several occasions. DNS is so vital to Windows 2000 Active Directory directory services that it's essential for you take time to learn about it in greater depth from such books as MCSE Training Kit—Windows 2000 Active Directory Services and MCSE Training Kit—Designing a Microsoft Windows 2000 Directory Services Infrastructure.
Nslookup is supplied with Windows NT and Windows 2000 and provides a means for diagnosing DNS problems. Nslookup can test forward and reverse lookup zones for servers and also list all the records held in a particular domain by a server. You'll use Nslookup to verify the DNS settings for the TRAINKIT domain in the following practice.
This practice will give you further experience setting up DNS records and verifying that the DNS server is working. The DNS server on TRAINKIT1 will be used for the trainkit.microsoft.com, the migrate.microsoft.co.uk domain to be created later in this chapter, and the migkit.trainkit.microsoft.com domains. You'll also configure reverse lookup (the service that maps IP addresses to names), which is required by the ADMT and ClonePrincipal tools that you'll be using.
When the Active Directory installation wizard installs DNS, it configures the loopback IP address for the server (127.0.0.1) as the address of the DNS server. The loopback address can cause problems when other systems attempt to determine the name of the DNS server in use. Therefore, if the DNS server is set to 127.0.0.1, you will need to configure TRAINKIT1 to be its own DNS server. This is an essential step that you should have completed in Chapter 8, but you'll check this setting again now.
To verify that TRAINKIT1 is its own DNS server
The Network And Dial-up Connections dialog box will appear.
The Local Area Connection Properties dialog box will appear.
The Internet Protocol (TCP/IP) Properties dialog box will appear.
To create a reverse lookup zone for trainkit.microsoft.com
The New Zone Wizard will appear.
Now you must enter the IP address range for which your DNS system will provide authority.
Figure 9.1 Identifying the reverse lookup zone
You must now manually create a pointer in the reverse lookup domain for trainkit1.trainkit.microsoft.com.
The New Resource Record dialog box will appear.
NOTE
Sometimes you won't see items even though they're in the DNS database. To see the items, you can press the F5 key to refresh the screen. If the refresh doesn't work, you can also try restarting the DNS service by right-clicking the TRAINKIT1 server in the DNS administrative tool, selecting All Tasks from the context menu, and then selecting Restart.
You're going to use the TRAINKIT1 server as the DNS server for the whole network. You must therefore create a zone for the (future) migrate.microsoft.co.uk domain and create a DNS entry for the MIGRATE1 domain installed on PC2. Perform the following tasks using the DNS administrative tool on TRAINKIT1.
To add the migrate.microsoft.co.uk zone to TRAINKIT1
The New Zone Wizard will appear.
The wizard will now ask you for the name of the domain to be created.
The summary page will now appear.
Note that the migrate.microsoft.co.uk zone has now appeared in the forward lookup zones.
You are now going to create another zone that will be used for the intra-forest restructure practice at the end of this chapter.
To add the migkit.trainkit.microsoft.com zone to TRAINKIT1
The New Zone Wizard will start up.
Note that the migkit.trainkit.microsoft.com zone has now appeared in the forward lookup zones.
Now that you have the zones in place, the hosts must be added to them. Once a host is in the zone, the DNS server can look up the host name and supply the matching IP address.
To add hosts to the zones
The New Host dialog box will appear.
A DNS message box appears to tell you the host was added.
Figure 9.2 Reverse lookup zones
For the migration exercises to work, MIGRATE1 in the MIGRATE domain (which will be used as the source for the migration) must be connected to a properly configured DNS server that has reverse lookup enabled.
To configure DNS on MIGRATE1
The Network dialog box will appear.
The Microsoft TCP/IP Properties dialog box will appear.
Now you're going to assign TRAINKIT1 to be the DNS server for MIGRATE1.
You now have a number of hosts enabled in the DNS. To verify their existence, you will now use the Nslookup program to check the host entries.
To verify the DNS service
The command-line program will start and should identify trainkit1.train-kit.microsoft.com as the default server with an IP address of 192.168.0.105.
The DNS server name and IP address should be displayed, followed by the IP address of MIGRATE1, 192.168.0.106. If it doesn't appear, check your DNS configuration.
ls trainkit.microsoft.com ls _t srv trainkit.microsoft.com
Notice the global catalog (gc) alias in the first command's listing.
What is the difference between these two commands?
A result of trainkit1.trainkit.microsoft.com should be displayed.
A result of migkit1.migkit.trainkit.microsoft.com should be displayed.
A result of migrate1.microsoft.co.uk should be displayed.
The Nslookup command will help you verify whether your DNS service is running correctly and help you test entries in the forward and reverse lookup zones.
Answers
In this lesson, you learned that DNS is core to Windows 2000 Active Directory and that if you don't plan your DNS structure properly, you might lose access to resources located on restructured servers. You learned how to set up forward and reverse lookup zones in Windows 2000 DNS and to add hosts for the zones. You also used the Nslookup utility to query your DNS database from a remote server.