INFX 504 - Networking for Information Professionals

Module 1 Lab #1: System Discovery

Name: ______Section: ______

Objective

The purpose of this lab is to introduce you to the methods for discovering your computer’s network connection, host name, MAC (Layer 2) address and network (Layer 3) address.

Scenario

This lab assumes you are using any version of Windows. You will go out and see your system’s host name, MAC address and network address. This is a non-destructive lab and you should be able to do it with your home machine without concern of changing your system configuration.

Ideally, this lab will be done in a classroom or other LAN with multiple computers connected to the Internet – even a home LAN.

Part 1

Use the Start menu to open the Command Prompt (DOS-like) window (Start | Pro-grams | Accessories | Command Prompt or Start | Run and type cmd Press Enter.
Type ipconfig and press Enter while in the command window. The following figure shows the Command screen. Ipconfig spelling is critical while case is not.

This first screen shows the IP address, subnet mask, and the default gateway. You should find that the IP address and the default gateway are in the same network or sub-net, otherwise this host wouldn’t be able to communicate outside the network. In the figure the subnet mask tells us that the first three octets must be the same to be in the same network.
Note: If you are on a LAN, you might not see the default gateway if you are running behind a Proxy Server.
Write down your IP address: ______
Write down your Subnet Mask: ______
Write down your Default Gateway: ______

Part 2

If you are doing this on a LAN, compare the information of several machines.

Are there any similarities? ______

What are similar about the IP addresses? ______

What are similar about the default gateways? ______

The IP addresses should share the same network portion. All machines in the LAN should share the same default gateway.

Record a couple of the IP Addresses? ______

______

Part 3

To see more info, type ipconfig /all and press ENTER. The figure shows the detailed IP configuration screen.

You should now see the host name (computer name, NetBIOS name), the DHCP server’s address, if used, and the date the IP lease starts and ends. Look over the information. You may see entries for a DNS server, which are used in name resolution.

Do all of the servers share the same network portion of the IP address as your work-station? It would not be unusual for some or all to be in another network. It means that your default gateway is going to forward (route) your requests to the other network.

The above figure reveals that the router is also performing DHCP and DNS services for this small network – this would be a small office / home office (SOHO) or small branch office implementation.

We also see the Physical Address (MAC) and the NIC card model (Description).

In the LAN, what similarities do you see about the Physical (MAC) Addresses?

______

While not a requirement many LAN administrators try to standardize components like NICS or computer models with built-in NICs, so it would not be surprising to find all machines share the first three Hex pairs in the adapter address. These three pairs identify the manufacturer of the adapter.

Write down the IP addresses of any servers listed: ______

______

Write down the computer’s Host Name: ______

Write down the Host Names of a couple other computers: ______

______

Close the screen when you are through looking around. Repeat the above steps as necessary to make sure that you can return to and interpret this screen.

Reflection

Based on what you observed today, what can you deduce about the following results taken from three computers connected to one switch?

Computer 1 / IP Address: 192.168.12.113
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.12.1
Computer 2 / IP Address: 192.168.12.205
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.12.1
Computer 3 / IP Address: 192.168.112.97
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.12.1

Should they be able to talk to each other – are they all on the same network? Why or why not? If something is wrong, what is most likely the problem?

Module 1 Lab #2: Connectivity Tools

Objective

In this lab you will learn to use the TCP/IP Packet Internet Groper (Ping) and Trace Route (Tracert) commands for testing connectivity in a network. In the process you will see name resolution occur using one or more DNS servers.

Scenario

This lab assumes you are using any version of Windows. This is a non-destructive lab and you should be able to do it with your home machine without concern of changing your system configuration.

Ideally, this lab will be done in a classroom or other LAN connected to the Internet. You will need the IP addresses that you recorded in Lab 1.

Part 1

Use the Start menu to open the Command Prompt window.

Type ping followed by the IP address of your computer – you wrote it down on the last exercise. The following figure shows the possible result of pinging your own IP address.

Ping uses the ICMP “echo reply” feature to test connectivity. Since it reports on four attempts, you have an indication of the reliability of the connection. Look over your results.Note: Windows 7’s firewall may prevent the pings from returning – appear to fail.

Try pinging the default gateway’s IP address if one was listed in the last exercise. If you can, it means you have physical connectivity to the router on your network and therefore probably the rest of the world.

If you are in a classroom or working with a second computer on the network, try pinging the IP address of another machine. Note the results. Try others in the LAN.

Try pinging the IP address of the DHCP and/or DNS servers listed in the last exercise. If it works for either server and they are not in your network, what does that tell you? It means your router is functioning as a default gateway to get you out.

Were you successful? ______

Part 2

Try pinging 127.0.0.1 although it can be any 127 address. The 127 network is reserved for loopback testing. If you can successfully ping the loopback address you know that TCP/IP is properly installed and functioning on this computer.

Were you successful? ______

Part 3

Try pinging

The first line of output shows you the Fully Qualified Domain Name (FQDN) followed by the IP address. A (Domain Name Service) DNS server somewhere out in the net-work was able to resolve the name to an IP address. DNS servers resolve Domain names (not host names) to IP addresses.

Without this name resolution, the ping would have failed because TCP/IP only under-stands valid IP addresses – not names. You would not be able to use your Web browser without this name resolution.

With DNS you can verify connectivity to computers on the Internet using familiar Web addresses (domain names) without having to know the actual IP address. If the nearest DNS does not know the address, it will ask a Server higher in the Internet structure.

Part 4

Try pinging .

Notice that the DNS server was able to resolve the name to an IP address, but you get no response. Microsoft routers have been configured to ignore ping requests. This is a security measure that many networks implement today.

Try to ping several other domain names including and you are aware of and record the results:

Example: IP: 207.46.28.116 Successful 4 times

______

Part 5

Try typing tracert and press ENTER.

Tracert is TCP/IP’s abbreviation for trace route. The preceding figure shows the possible result when running tracert from Bavaria in Germany. The first line of output shows you the Fully Qualified Domain Name (FQDN) followed by the IP address. So we know that a DNS server was able to resolve the name to an IP address. Then there are listings of all routers the Tracert requests had to pass through to get to the destination.

Tracert actually uses the same echo requests and replies as the ping command but in a slightly different way. You should see that Tracert actually contacted each router three times. By comparing the results we can gauge the consistency of the route. Notice in the above example that there were relatively long delays after router 11 and 13, possibly due to congestion. The main thing is that there seems to be relatively consistent connectivity.

Each router represents a point where one network connected to another and your packet was forwarded through.

Note: If you get a couple rows of stars, the destination device has probably been configured to not reply to PINGs. Press [Ctrl]+c to stop the command.

Part 6

Try tracert on other domain names or IP addresses like Yahoo and record the results:

Example: IP: 207.46.28.116 It is 14 hops (routers) away

______

Part 7

In this next exercise, we will use the nslookupcommand and DNS feature to find the IP address(es) for a domain name or any domain names associated with an IP address. Either way a domain name query packet is sent to a designated (or defaulted) DNS server for resolution. An example of each form:

C:\>nslookup

Server: ns11.attbi.com

Address: 204.127.199.8

Non-authoritative answer:

Name:

Address: 198.133.219.25

C:\>nslookup 198.133.219.25

Server: ns11.attbi.com

Address: 204.127.199.8

Name:

Address: 198.133.219.25

C:\>

Note: Many searches by IP address will fail because of company security implementations.

In the command window, try:

nslookup

What is the IP address(es)? ______

nslookup 207.200.74.2

What is the Domain Name? ______

Try any domain names you like and record the IPs.

Module 1 Lab #3: Binary to Decimal Conversion

Objective

In this exercise you will practice converting binary values to decimal values.

Back ground

Binary data is made up of ones and zeros (on and off). While binary data can be grouped in varying increments like 3 or 4 digits (110 or 1011), in TCP/IP it is usually grouped in eight digit groups called a Byte.

A Byte (8 bits) can range from 00000000 to 11111111 creating 256 combinations with decimal values ranging from 0 to 255. IP addressing uses 4 bytes (32 bits) to identify both the network and specific device (node). The example at the top of this lab is an example of an IP address in both binary decimal formats.

A simple tool for easily converting Binary to Decimal values is the following table. The first row is created by counting right to left from one to eight for the basic eight bit positions (although it would work for any size binary value). The value row starts with one and doubles (base 2) for each position to the left.

Steps

Type the binary bits (for example 10111001) in row three.
Put the decimal values in row four only for the third row 1s. Technically the row two values are being multiplied by row three.
Now just sum row four (across).

Practice

Convert the following binary values to decimals:

1) 1110______

2) 100110______

3) 11111111______

4) 11010011______

5) 01000001______

6) 11001110______

7) 01110101______

8) 10001111______

9) 11101001.00011011.10000000.10100100 _____._____._____._____

10)10101010.00110100.11100110.00010111 _____._____._____._____

Module 1 Lab #4: Decimal to Binary conversion

Objective

In this exercise you will practice converting decimal values to binary values.

Back ground

The same conversion table and simple division can be used to convert Decimal values to Binary.

Steps

Say we want to convert 207 to binary.

Start with left-most value (largest) and see if the decimal value can be divided by it. Since it will go once, we put a 1 in row three of the conversion table and calculate the remainder (79).
Since the remainder can be divided by the next value (64), put a 1 in row three of the table.
Since the remainder cannot be divided by either 32 or 16 we put 0s in row three of our table.
We continue until there is no remainder.
If necessary, use row four to check your work.

Practice

Convert the following decimal values to binary:

1) 123______

2) 202______

3) 67______

4) 7______

5) 252______

6) 91______

7) 116.127.71.3______.______.______.______

8) 255.255.255.0______.______.______.______

9) 192.143.255.255______.______.______.______

10) 12.101.9.16______.______.______.______

2012Bob Larson (iSchool – University of Washington)Page 1of 11