You should now see a Confi rmation window Figure 6-2. Review the information

132 | Lesson 6 When complete, the Results should show that the installation succeeded. Click Close to fi nish. This will authorize the server. At this point, the DHCP server is ready to hand out IP addresses to client computers.

3. Go to a Windows client computer and obtain an IP address automatically:

a. Access the IPv4 Properties dialog box for the wired network adapter.

b. Select the Obtain an IP address automatically radio button.

c. Click OK for all dialog boxes.

d. Open the command prompt and type ipconfi g all. You should obtain an

IP address automatically from the list of IP addresses in the DHCP server’s IP scope. Most likely, it will be the fi rst one on the list: 192.168.1.150.

e. If, for some reason, you cannot obtain an IP address, check your confi gura-

tion settings on the server. Also, on the client, you can attempt an ipconfi g release and ipconfi g renew to retry obtaining an IP address. In some cases, you might obtain an IP address from another DHCP device or server. If this is the case, remove that device from the network. If your client has obtained an address on the 169.254.0.0 network, then APIPA has intervened and self- assigned an IP address. See the next exercise for information about how to dis- able APIPA.

f. Test your new IP address by pinging the IP address of the DHCP server and

another client on the network. Disable any fi rewalls that might block pings.

4. When you are finished, return the client computers to normal. If necessary, access the

server and stop the DHCP service. Figure 6-2 DHCP Confirmation window Working with Networking Services | 133 DISABLE APIPA GET READY. Sometimes, APIPA can get in the way of a client obtaining an IP address properly e.g., when a client attempts to obtain an IP address from a DHCP server, but the DHCP server is too busy. At that point, APIPA would self-assign an IP address to the client computer, and the computer would be stuck with that address until an ipconfig release and renew was run from the command line. Depending on the version of Windows and the configuration, this still might not be enough. If you see an IP address of 169.254. x.x, then you know that the client has self-assigned an IP address with the help of APIPA. This shouldn’t happen often, but you never know. Just in case, here’s how to disable APIPA in the Registry: 1. Access the Registry by pressing Windows + R on the keyboard and typing regedit.exe. 2. Navigate the following path: Computer HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services Tcpip Parameters Interfaces

3. In the Interfaces subkey, find the network adapter on which you wish to disable

APIPA. The best way to do this is to find the current IP address of the network adapter with an ipconfig, then locate that adapter in the registry by searching through each of the interfaces one at a time and examining the IPAddress entry.

4. Right click the right pane and select New DWORD.

5. Name the new dword ipautoconfigurationenabled.

6. Then, make sure the entry is set to zero. This is the disabled setting. An example of

this is shown in Figure 6-3. Once APIPA is disabled, it will not interfere with the client’s particular network adapter attempting to obtain an IP address. However, this does not ensure that the client will receive an IP address. Always verify that the DHCP server is configured properly and connected to the network. Figure 6-3 Disabling APIPA