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Understanding Domains and Name Resolution


Computers have no problems using IP addresses to locate other networks and hosts. The average user, however, can have trouble remembering those dotted-decimal addresses. Domain names and computer names make specifying the addresses or other networks or hosts much easier.

A domain name is a unique named formatted much like an IP address, except that the domain name uses words rather than numbers. The domain name identifies your network and is associated with your network's IP address. If your company is Foo Fang Foods, Inc., for example, your departmental subnet might be known as sales.foofang.com. The first portion, sales, identifies your subnet. The second portion, foofang, identifies your corporate network. The last portion, .com, specifies the type of organization, and in this example, indicates a commercial network. Other common designators are .gov for government, .edu for education, .mil for military, .org for noncommercial organizations, and .net for networking organizations.

Tip
As with your IP address, your domain must be unique. If you connect your network to other networks or to the Internet, contact the InterNIC to apply for a unique domain name.


 

A computer name specifies a host on the subnet. Your host computer name is combined with your domain to derive your Internet address. Your host name doesn't have to match your computer's name that identifies it in its workgroup, but it can. By default, Windows 98 uses as your host name the NetBIOS computer name you specify during setup, but you can specify a different name when you configure TCP/IP. Whatever name you specify as the computer name in the TCP/IP configuration is registered with the network when Windows 98 starts.

Note
The computer name you specify for your computer when you install Windows 98 is its NetBIOS name. A computer's NetBIOS name bears no relationship to its host name under TCP/IP. The two names can be different or the same.


 

No direct translation or correlation exists between IP addresses and domain names and host names. Some method, therefore, is required to enable computers to look up the correct IP address when a user specifies a name rather than an IP address. Your Windows 98 host can use one of two methods: DNS or WINS.

Note
For a technical discussion of DNS and WINS, you can consult volume 2 of the Microsoft Windows NT Resource Kit, "Windows NT Networking Guide," or consult the Windows 98 Resource Kit on the Windows 98 CD.


 

Understanding DNS

DNS stands for Domain Name System. DNS is a distributed database system that enables a computer to look up a computer name and resolve the name to an IP address. A DNS name server maintains the database of domain names and their corresponding IP addresses. The DNS name server stores records that describe all hosts in the name server's zone.

If you use DNS for your Windows 98 workstation, you specify the IP address of one or more DNS servers in your TCP/IP configuration. When your workstation needs to resolve a name into an IP address, it queries the DNS servers. If the server doesn't have an entry for the your specified name, the name server returns a list of other name servers that might contain the entry you need. The workstation then can query these additional name servers to resolve the name.

Tip
You can define multiple DNS servers in your Windows 98 TCP/IP configuration.


 

Besides a DNS server, you can use the Hosts file to resolve host.domain-formatted names to IP addresses.

Understanding WINS

WINS stands for Windows Internet Name Service. WINS provides a dynamic database for managing name resolution. WINS relies on a Windows NT server to act as a WINS server. When you install TCP/IP on your workstation, the client software necessary to connect to a WINS server is installed automatically. One advantage of using WINS is that it's dynamic, rather than static like DNS. If you use DHCP to assign network addresses, WINS automatically updates the name database to incorporate DHCP IP address assignments. As computers move from one place (and address) to another on the network, the WINS server automatically updates and maintains their addresses.

Another advantage of using WINS is that it includes NetBIOS name space, which enables it to resolve NetBIOS names into IP addresses. Assume that your computer's NetBIOS name is joeblow, your computer's TCP/IP host name is JoeB, and your domain name is bozos.are.us. A DNS server could only resolve JoeB.bozos.are.us, but a WINS server could resolve JoeB.bozos.are.us and joeblow.bozos.are.us into the correct IP address.

Tip
The Microsoft Windows NT Resource Kit contains a good technical explanation of other advantages WINS offers.


 

When you configure TCP/IP in Windows 98, you can specify the IP addresses of up to two WINS servers to handle name resolution. If your network uses DHCP, you can configure your workstation to resolve the addresses of WINS servers dynamically using DHCP.

If you don't have a WINS server available to provide name resolution of NetBIOS computer names to IP addresses (such as resolving your computer's name to its IP address), you can use the Lmhosts file to resolve NetBIOS names.