CLICK OK TO CLOSE THE LOCAL AREA CONNECTION PROPERTIES DIALOG BOX,...

6. Click OK to close the Local Area Connection Properties dialog box, and then close

the Network And Dial-Up Connections window.

On the CD At this point, you should view the multimedia presentation “The Role of DHCP in the Network Infrastructure,” which is available in the Multimedia folder on the CD-ROM accompanying this book. This presentation provides valuable insight into how DHCP works on a network.

What Is Automatic Private IP Addressing?

The Windows XP Professional implementation of TCP/IP supports automatic assign-

ment of IP addresses for simple LAN-based network configurations. This addressing

mechanism is an extension of dynamic IP address assignment for LAN adapters,

enabling configuration of IP addresses without using static IP address assignment or

using a DHCP server. Automatic Private IP Addressing (APIPA) is enabled by default

in Windows XP Professional so that home users and small business users can create a

functioning, single-subnet, TCP/IP-based network without having to configure the

TCP/IP protocol manually or set up a DHCP server.

Note The IANA has reserved 169.254.0.0 through 169.254.255.255 for APIPA. As a result, APIPA provides an address that is guaranteed not to conflict with routable addresses.

APIPA assigns an IP address and subnet mask only, and configures no additional

parameters. This service is very useful in smaller, single-network environments in

which there is no need for connectivity to other networks. APIPA provides a very sim-

ple way to configure TCP/IP; the network administrator does not need any knowledge

of the necessary configuration parameters. However, if connectivity to other networks

is required, or if the client requires name-resolution services, APIPA is not sufficient.

APIPA does not provide a default gateway or name server address to the client.

The process for the APIPA feature, shown in Figure 13-4, is explained in the following

steps: