Lesson 1

Determining Name Resolution Requirements

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Lesson 1: Determining Name Resolution Requirements

Name resolution is an essential function on all TCP/IP networks, and the network infra-

structure design process includes a determination of what names your computers will

use, and how those names will be resolved into Internet Protocol (IP) addresses. As

with IP addressing itself, the names you choose for your computers are affected by

your network’s interaction with the Internet and by the applications the computers are

running.

After this lesson, you will be able to

■ Understand the construction of DNS names

■ Explain the DNS name resolution process

■ List the NetBIOS name resolution processes supported by computers running the

Microsoft Windows operating system

■ Determine what types of name resolution mechanisms you must deploy on your network

Estimated lesson time: 40 minutes

What Is Name Resolution?

TCP/IP communications are based on IP addresses. Every IP datagram transmitted by

a TCP/IP computer contains a source IP address, which identifies the computer send-

ing the datagram, and a destination IP address, which identifies the computer that is to

receive it. Routers use the network identifiers in the IP addresses to forward the data-

grams to the appropriate locations, eventually getting them to their final destinations.

Off the Record Computers are able to read and process IP addresses easily, but human

beings unfortunately cannot. It is not practical to expect people to remember the 32-bit IP

addresses associated with Web sites, file system shares, and e-mail addresses, so it has

become common practice to assign friendly names to these resources. This is why you use

names like www.adatum.com for Internet Web sites, access the computers on your network

by browsing among a list of names instead of IP addresses, and address e-mail messages to

marklee@adatum.com, rather than to marklee@10.1.54.87.

Friendly names are only for use by people; they do not change the way the TCP/IP

computers communicate among themselves. Whenever you use a name instead of an

address in an application, the computer must convert the name into the proper IP

address before initiating communications with the target computer. This name-to-

address conversion is called name resolution. When you type the name of an Internet

server in your Web browser, the first thing your computer does is resolve that name