ITNW 1353 – Supporting Network Server Infrastructures
Prof. Michael P. Harris
(Version 20070207)
Lab #2 - Automatic Private IP Addressing (APIPA) in Microsoft Windows
Objective:
To identify when a Windows host (computer) has automatically configured its IP address
without using the DHCP (Dynamic Host Configuration Protocol).
Background:
There are two methods for a host to be automatically assigned an IP-address. The first is
through DHCP and the second is through APIPA. The idea behind Automatic Private IP
Addressing was to make the setup of small workgroups an easy and automatic process, but
it also serves to make sure your NIC is configured to connect to your network even when the
DHCP server is off-line. In this lab you will view the results of both DHCP and APIPA host
configuration. You will also use a variety of tools to test for connectivity between hosts.
Lab Worksheet:
I. DHCP configuration
1. Use the ipconfig [/all] command to find the following information:
1. Host IP-Address:
__________________________
2. Subnet Mask:
__________________________
3. Default Gateway:
__________________________
4. DNS:
__________________________
5. Host Name:
__________________________
6. Domain Name:
__________________________
These are the six (6) necessary pieces of information for IP configuration.
2. For dynamic host IP configuration, there is a seventh necessary configuration item
needed. Use the same command to find the IP-address of the
7. DHCP server:
__________________________
Note that when using DHCP, the first six items are automatically filled-in.
3. To configure a host to use DHCP, what is the ‘name’ of the configuration option
within Microsoft Windows?
____________________________________________________
4. Use the ping command to test connectivity between your host and the DHCP server.
Write down the complete command that you typed at the DOS prompt.
____________________________________________________
5. Was the ping successful?
__________________________
II. Automatic Private IP Addressing
1. Make sure your hosts are configured to use DHCP. Shut-down your workstations.
Obtain an Ethernet hub/switch and connect three to four host workstations to the
same hub. Restart the host systems. How can you tell if the physical connection to
the hub/switch is good? What does the word Link really mean?
2. At this point would you expect your workstation to have an IP-address?
3. If you attempt to ping the DHCP server, would your ping be successful? Why?
4. Repeat step 4 of part I to see if your prediction was correct in question #3. Based on
the results of your ping command is the DHCP server available?
5. Check your network connectivity. Are you on-line? How do you know?
Ping your own host. Were you successful? What is a loopback address?
6. Record again the IP-configuration information for your host workstation.
1.
2.
3.
4.
5.
6.
7.
Host IP-Address:
Subnet Mask:
Default Gateway:
DNS:
Host Name:
Domain Name:
DHCP server:
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
Note: if your IP-address is the same as in part I, you may need to use the command
ipconfig /release followed by ipconfig /renew
7. Record this same information for each workstation connected to your hub.
1.
2.
3.
4.
5.
6.
7.
Host IP-Address:
Subnet Mask:
Default Gateway:
DNS:
Host Name:
Domain Name:
DHCP server:
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
Use the ping command to reach out and touch each neighbor on your network. Put a
 next to each host-name if successful and an  if unsuccessful.
III. Network Examination:
These next few questions will help you notice some things about your new network.
1. What do all of the above IP-addresses have in common?
2. How does the APIPA process prevent the assignment of duplicate IP addresses? DHCP
performs this same test to prevent duplicates.
(hint… it uses the same command you used in this lab)
3. What is a “Private” IP-Address?
4. List the three most commonly used private IP-address classes (ranges).
5. Suppose you come in to this class first thing in the morning and start up your
computer but when you go to surf the net you get an error message. You do some
checking and find that your IP-address is 169.254.15.26 -how does this
information help you in the troubleshooting process?
IV. Clean Up
Connect your system back up to the college network and issue the commands
ipconfig /release followed by ipconfig /renew. Confirm that your host is once
again part of the delmar.edu network. Show your IP-address and check that IE is working
properly by connecting to mydmc.delmar.edu and our class web-page.
Notes: This lab assumes you are using DHCP on your network and your workstations are
running Windows. When you run ipconfig /all you should see that both DHCP and APIPA
are enabled. If DHCP fails, then Windows performs an APIPA auto-configuration and
assigns itself an IP-address.