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Lesson 1
Determining Name Resolution Requirements
4-3
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
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