Franske CNT-2300 Advanced Networking Lab

In this lab students, working in partners or small groups, will utilize tools in Windows XP for troubleshooting a network connection as well as setup a secure wireless network.

Part 1: Windows XP Network Troubleshooting Tools

This part of the lab will be accomplished on a system in the regular classroom.

Lab Background

One of the most common and frustrating problems for users is a network connection which is not working properly. As a PC technician you will frequently be called upon to troubleshoot, diagnose and repair network connections. One of the most useful skills when evaluating network problems is that of isolating the problem. Determining where the problem is either in the local computer or with a specific network device will aid in finding a speedy fix for the problem or bringing it to the attention of the appropriate personnel be that a network manager or Internet Service Provider (ISP).

Command Line Network Troubleshooting

1. Open a command prompt window (Start -> Run -> "cmd")
2. Type ipconfig and press Enter. In your lab notebook record the name of the three values displayed for each network adapter.
3. Additional details about the TCP/IP configuration of the system can be obtained by the ipconfig /all command. Run this command and answer the following questions in your lab notebook about your primary network connection (the one used to connect to the Internet):
   1. What is the IP address of this connection?
   2. What is the default gateway address for this connection?
   3. What is one of the DNS server addresses for this connection?
   4. What is the Primary WINS server address for this connection?
4. Sometimes you may want to obtain a new IP address from the DHCP server in order to try and resynchronize the network connection. Attempt to do this by issuing the ipconfig /release command followed by the ipconfig /renew command. Record in your lab notebook whether you got a different IP address than you previously had.
5. View additional information about your DHCP address lease by issuing the ipconfig /all command.
6. The domain names of computers on the Internet are resolved using a domain name server. If your computer has an incorrect or improperly working domain name server you will be unable access websites by name. You can test the network connection independent of a nameserver by attempting to connect to or ping a computer directly by IP address. One such Internet accessible address is a nameserver belonging to Verizon with the address of 4.2.2.2. Try pinging this address to test your connection to the Internet by issuing the ping 4.2.2.2 command and recording the results in your lab notebook.
7. It is also possible to test the nameserver by asking it to resolve a domain name into an IP address with the nslookup command. Try issubing the nslookup google.com command. In your lab notebook record the name and address of the nameserver which responded to your request as well as at least one of the IP addresses for the Google website.
8. If there is a problem connecting to the Internet you may be able to narrow down where the problem is occurring by tracing a route through all the network devices between you and the site you are attempting to access. This can be done with the tracert command which will display a list of each "hop" or router along the path from you to the remote site. Try tracing the route to both Google and the 4.2.2.2 Verizon nameserver using the tracert google.com and tracert 4.2.2.2 commands. Record some of the results in your lab notebook:
   1. Which site has a shorter route as determined by "hop count" or the number of routers which must be used to reach the destination and how many hops are there for that route?
   2. By comparing the traced routes to several sites you can determine what the path is from your computer to the Internet (this would be the first several hops common to all your traceroutes). How many hops is it from your computer to the Internet at large?
9. In addition to DNS the Windows operating system uses special name servers for machines on the local network (such as for file and printer sharing) called WINS servers. Though it is not possible to use the nslookup command with these servers you can query them for a list of machines on the local network which they are aware of. Try issuing the net view command to list machines on the local network the WINS server is aware of and list at least one of the machines in your lab notebook.
10. Be prepared to answer any questions about these troubleshooting utilities and how you might use them to narrow down a problem.
11. Return any settings on your computer to the original configuration and ensure that Internet access is working properly

Part 2: Securing a Wireless Network

This part of the lab will be accomplished using laptops NOT connected to the school campus network.

Lab Background

Wireless networks have become a pervasive part of the modern network but they also have some additional security concerns not typically a problem in wired networks. While there are many ways to deal with these concerns, and complex enterprise networks have special requirements, one of the simplest things which you can do to protect one of these networks is to enable appropriate security (WPA NOT WEP). In this lab you will setup a basic wireless network such as one commonly found in a home and then secure it using WPA.

Lab Steps

1. If you are not already familiar with the Linksys 300N router research it online and determine how to perform a factory reset as well as the default administrator username and password
2. Cable a basic network connecting one laptop with a cable to the 300N router, you will also need one of the silver laptop computers. DO NOT connect the router or either computer to the campus network!
3. Reset your Linksys 300N router following the instructions you found in step 1
4. Make sure the computers are set to receive automatic addressing
5. Connect to the administrative interface on your router using the wired computer and enable the wireless network (unsecured), set the name or SSID of the network to something specific and unique to your group
6. Connect to your wireless network with the laptop and attempt to ping the desktop computer. You may need to check and modify the firewall settings on one or more of the computers to allow this.
7. Select and set a secure WPA passphrase for wireless access to your network through the Linksys 300N administrative interface.
8. Try to reconnect to your wireless network from the laptop and make sure you are not able to do so without entering the passphrase
9. Try pinging between the wired and wireless computers and make sure the secured wireless network is operating properly.
10. Return your system to the original settings and reset your Linksys router to the factory defaults

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