Fundamentals of Networking

Building your first network

As your first network lab you are going to look on performing basic configurations in network nodes and configuring a network. In detail you will be configure the switch management interface and implement basic connectivity between two user terminals. You are going to learn about basic but useful diagnostic commands for networking.

Task 1 (Directed)

Open Packet Tracer and get familiar with packet tracer interface. From the device selection box try and find the PCs and the switches as shown in Figure 1 Basic topology. Place them in your workspace the white empty area where topologies are created and simulations are displayed.

Using the addressing table above we need to configure the PCs:

1. Click PC1, and then click the Desktop tab.

2. Click IP Configuration. In the Addressing Table above, you can see that the IP address for PC1 is 192.168.1.1 and the subnet mask is 255.255.255.0. Enter this information for PC1 in the IP Configuration window.

3. Repeat steps 1 and 2 for PC2 remembering that PC 2 has an IP address of 192.168.1.2.

Let us test if the two PCs can communicate:

4. Click PC1. Close the IP Configuration window if it is still open. In the Desktop tab, click Command Prompt.

5. Type the ping command and the IP address for PC2, and press Enter. Packet Tracer PC Command Line 1.0 PC> ping 192.168.1.2

Task 2 (Directed)

It is time to configure the switches:

1. Click Switch 1, and then click the CLI tab.

2. Enter privileged EXEC mode by entering the enable command.

3. Examine the running configuration by running the show running-config command.

4. Enter config mode by running configure terminal command.

5. Change the host name to S1-GR by entering hostname S1-GR.

6. Run the exit command to exit from the config mode.

You are now able to configure your switch. Usually, before configuring you would need to take some security measures, such as securing your console and securing the privilege mode access.

8. Run the following set of commands to secure your console:

   Terminal

   S1-GR#configure terminal<OR>config t 
   Enter configuration commands, one per line. End with CNTL/Z. 
   S1-GR (config)#line console 0 
   S1-GR (config-line)#password <enter your name> 
   S1-GR (config-line)#login 
   S1-GR (config-line)#exit 
   S1-GR (config)#exit 
   %SYS-5-CONFIG_I: Configured from console by console S1-GR #
   

   Exit everything and verify that the password has been set up correctly.

9. Run the following set of command to secure privileged mode access:

   Terminal

   S1-GR >enable 
   S1-GR #configure terminal 
   S1-GR (config)#enable password green 
   S1-GR (config)#exit 
   %SYS-5-CONFIG_I: Configured from console by console 
   S1-GR #
   

10. Again, verify the privileged mode is secure.

11. Save configuration to NVRAM. To do this you would need to copy the running configuration to startup configuration:

    Terminal

    copy running-config startup-config
    

12. Repeat Steps for S2.

13. Try and verify if there is communications between the PCs and any of the switches

Task 3 (Not Directed)

14. Configure S1 and S2 with an IP address.

15. Switches can be used as plug-and-play devices. This means that they do not need to be configured for them to work. Switches forward information from one port to another based on MAC addresses.

    If this is the case, why would we configure it with an IP address?

    To connect remotely to a switch, you need to assign an IP address to it. The default configuration on the switch is to have the management of the switch controlled through VLAN 1.

16. After answering 15, research and try to configure the VLAN 1 to have an IP address of 192.168.1.132 and 192.168.1.133 for S1-GR and S2-GR respectively. Do not forget to save configurations to NVRAM.

    • Look at the following commands to do this:

      • Interface
      • ip address
      • no shutdown

    • Solution

      S1# configure terminal
      
      Enter configuration commands, one per line.  End with CNTL/Z.
      
      S1(config)# interface vlan 1
      
      S1(config-if)# ip address 192.168.1.253 255.255.255.0
      
      S1(config-if)# no shutdown
      
      %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
      
      S1(config-if)#
      
      S1(config-if)# exit
      
      S1#
      

17. Once you are confident that you have set it up verify your connections using ping command.

Task 4

18. Question:

    Why do you enter the no shutdown command?

    The no shutdown command administratively places the interface in an active state.

19. Configure S2 with an IP address.

    • Use the information in the Addressing Table to configure S2 with an IP address.

20. Verify the IP address configuration on S1 and S2.

    • Use the show ip interface brief command to display the IP address and status of all the switch ports and interfaces.

    • You can also use the show running-config command.

21. Save configurations for S1 and S2 to NVRAM.

22. Question:

    Which command is used to save the configuration file in RAM to NVRAM?

    copy running-config startup-config

23. Verify network connectivity.

• Network connectivity can be verified using the ping command.

• It is very important that connectivity exists throughout the network.

• Corrective action must be taken if there is a failure. Ping S1 and S2 from PC1 and PC2.

  • Click PC1 and then click the Desktop tab.
  • Click Command Prompt.
  • Ping the IP address for PC2.
  • Ping the IP address for S1.
  • Ping the IP address for S2.