Configure Network Services - MCSA Windows Server 2012 R2: Installation and Configuration Study Guide - page 57

them the name (Microsoft), and get the telephone number. You would then make the call.
Now think about trying to connect to Server1. You don't know the TCP/IP number (the
computer's telephone number), so your computer asks DNS (information) for the number of
Server1. DNS returns the number, and your system makes the connection (call). DNS is your
network's 411, or information, and it returns the TCP/IP data for your network.
TCP/IP is actually a collection of different technologies (protocols and services) that
allow computers to function together on a single, large, and heterogeneous network.
Some of the major advantages of this protocol include widespread support for hardware,
software, and network devices; reliance on a system of standards; and scalability. TCP
handles tasks such as sequenced acknowledgments. IP involves many jobs, such as logical
subnet assignment and routing.
The Form of an IP Address
To understand DNS, you must first understand how TCP/IP addresses are formed. Because
DNS is strictly on a network to support TCP/IP, understanding the basics of TCP/IP is
extremely important.
Microsoft exams cover TCP/IP. The TCP/IP material will be covered in Chap-
ter 8, “Configure TCP/IP.”
An IP address is a logical number that uniquely identifies a computer on a TCP/IP
network. TCP/IP allows a computer packet to reach the correct host. Windows Server 2012
R2 works with two versions of TCP/IP: IPv4 and IPv6. An IPv4 address takes the form of
four octets (eight binary bits), each of which is represented by a decimal number between
0 and 255. The four numbers are separated by decimal points. For example, all of the
following are valid IP addresses:
■ 128.45.23.17
■ 230.212.43.100
■ 10.1.1.1
The dotted decimal notation was created to make it easier for users to deal with IP
addresses, but this idea did not go far enough. As a result, another abstraction layer was
developed, which used names to represent the dotted decimal notation—the domain
name. For example, the IP address 11000000 10101000 00000001 00010101 maps
to 192.168.1.21, which in turn might map to server1.company.org , which is how the
computer's address is usually presented to the user or application.
As stated earlier, IPv4 addresses are made up of octets, or the decimal (base 10)
representation of 8 bits. It takes four octets to add up to the 32 bits required. IPv6 expands
the address space to 128 bits. The address is usually represented in hexadecimal notation as
follows:
2001:0DB8:0000:0000:1234:0000:A9FE:133E