Using DNS on Multihomed Computers, Part 1
One of the key features of Windows 2000 is its dynamic DNS. By simply providing a client with the IP address of a DNS server, the client is able to automatically register its name when it comes on-line. Unfortunately, this normally simple process can get a bit hairy on Multihomed computers. Multihomed computers are computers that use two or more network cards. For example, you may have need for the various network adapters to have their own individual DNS names, or you may not want for one of the adapters to be registered at all. In this article, I'll address some of the issues that you'll encounter when configuring DNS on Multihomed computers.
Configuring each network adapter with a different DNS name is called setting a connection specific domain name. For example, if you had one network adapter connected to the Internet and another adapter connected to the local network, you might use two entirely different domain suffixes. For example, the Internet related connection might use the domain suffix mycompany.com, while the network adapter attached to the local network may need a domain suffix such as mynetwork.com.
To establish connection specific DNS naming conventions, right click on My Network Places and select the Properties command from the resulting context menu. When you do, you'll see the Network and Dial Up Connections window appear. Windows uses a separate connection icon for each network adapter. This separation gives you the chance to configure the two adapters independently. To do so, right click on the network connection that you want to configure and select the Properties command from the resulting context menu. You'll now see the connection's properties sheet. At this point, select Internet Protocol (TCP/IP) from the components list and click the Properties button. When you do, you'll see the Internet Protocol (TCP/IP) Properties sheet. Next, click the Advanced button to access the Advanced TCP/IP Settings properties sheet and then select the DNS tab. Now, simply fill in the DNS Suffix For This Connection text box with the desired DNS suffix.
Registering multiple DNS suffixes is easy to do, but there may be times when you don't want to register a connection at all. Remember that registering a DNS connection allows other computers to locate your computer by name instead of having to know the computer's IP address. Occasionally, for security reasons though, you may not want one of the network adapters to be registered in the DNS database. To prevent a network adapter from being registered, return to the Advanced TCP/IP Settings properties sheet's DNS tab and unselect the Register This Connection's Address in DNS check box.
As you can see, when you're using Multihomed computers, you'll have to be very careful with the way that you configure the DNS registration for each adapter. In Part 2, I'll continue the discussion by explaining some more issues that you may encounter when performing DNS registrations on Multihomed computers.
Brien M. Posey is an MCSE who works as a freelance writer. His past experience includes working as the director of information systems for a national chain of health care facilities and as a network engineer for the Department of Defense. Because of the extremely high volume of e-mail that Brien receives, it's impossible for him to respond to every message, although he does read them all.