The MCSE and MCSA exams will undoubtedly test your knowledge of DNS and DHCP. One of the things you will definitely need to be up to speed on is how these two services can integrate.

Remember, pre-Windows 2000 platforms used NetBIOS names to identify clients and servers on the network and the services that they are running. Name resolution was facilitated using WINS, LMHOSTS, or through broadcasts. WINS and DHCP could easily be integrated because the WINS database was dynamic.

Windows 2000 and Windows Server 2003 use DNS to locate clients, servers, and services on the network. Prior to the ability to integrate DNS and DHCP, administrators would have to manually add host records to the DNS database. It could also pose a problem when clients were using DHCP for IP addressing.

To overcome this and allow DHCP and DNS to be integrated on a network without the use of a WINS, Windows 2000, Windows XP, and Windows Server 2003 machines configured as DHCP clients can be automatically registered in the DNS database.

It is very important that you know how the different clients update their host records. Clients running Windows 2000 and later can send updates their host records directly with the DNS server. Or the client can request that the DHCP server make the update on its behalf. Clients running platforms earlier than Windows 2000 do not support dynamic updates and are unable to interact directly with a DNS server. In this case, the DHCP server can be configured to perform the updates on behalf of these legacy clients.

You can configure DHCP for DNS integration through the DHCP console. Simply right click the DHCP server and click the Properties option. You will see five different options, each of which is summarized below. Make sure you are familiar with each one before taking your exam.

• Enable DNS dynamic updates according to the settings below - By default, this option is enabled.
• Dynamically update DNS A and PTR records only if requested by the DHCP clients - This option is also selected by default so the DHCP server will perform the updates if requested to do so by the client.
• Always dynamically update DNS A and PTR records - if you select this option the DHCP server will always update DNS A and PTR records on behalf of DHCP clients.
• Discard A and PTR records when the lease is deleted - The DHCP server will discard the records when a DHCP client lease expires.
• Dynamically update DNS A and PTR records for DHCP clients that do not request updates (for example, clients running Windows NT 4.0) - Select this option if there are clients on the network that do no support dynamic updates, such as those clients running Windows NT 4.0. In such cases, the DHCP server will perform the updates on behalf of the client.