Networking 101

Copyright Priscilla Oppenheimer

Lab 5 Managing Routers, Firewalls, and Switches

Scenario

You are a network administrator working for a large company. The users are complaining that the network is slow. Your job is to open a management (console) connection to a switch, router, or PIX firewall and to check the device's configuration and status for problems that might be causing the network to be slow.

Steps

  1. Connect to one of the network devices (switch, router, or PIX firewall) using a rollover console cable.
    1. Pick out a rollover cable.
    2. Connect the cable from the COM1 port on your PC to the device's console port.
  2. Open a HyperTerminal session on the PC so that you can manage the device.
    1. Locate the HyperTerminal program. (Start>Programs>Accessories>Communications>HyperTerminal.)
    2. Start HyperTerminal
    3. Name your session something like cisco.
    4. In the Connect To window, use the Connect Using drop-down menu to select COM1 and click OK.
    5. In the COM1 Properties window, use the drop-down menus to select the following:
      1. Bits per second = 9600
      2. Data bits = 8
      3. Parity = None
      4. Stop bits = 1
      5. Flow control = none
    6. Click OK. Press Enter a few times. You should see some characters from the device that you are managing.
  3. Verify the status of the device with the following commands.
    1. Type enable and Enter. Type the enable password, provided by the instructor.
    2. Check CPU utilization on the device.
      1. On a router or switch, use the show processes cpu command.
        1. Only the first line of output is very useful. Type CTRL-C to stop it showing you information about every single process.
      2. On the PIX firewall, use the show cpu usage command.
    3. See if there are lots of errors on the interfaces with the show interface command.
    4. Check memory usage and statistics with the show memory command.
    5. Check version information and information about the type of platform (CPU, etc.) with the show version command.
    6. View the configuration of the device with the show running-config command.
  4. Check and test reachability information on the device.
    1. On a switch or router you can look at information about your neighbors that the Cisco Discovery Protocol (CDP) gathers with the show cdp neighbors detail command. (This command doesn't work on the PIX firewall. If you are on a PIX, just continue to the next step.)
    2. Try to ping your neighbors.
    3. Try a trace route (the command is trace) to reach your neighbors.
    4. Investigate information that the device uses for forwarding traffic.
      1. If you are on a switch, use the show mac-address-table command.
      2. If you are on a router, use the show ip route command.
      3. If you are on a PIX firewall, use the show route command.
  5. Change the banner that the device displays when someone accesses it for management purposes. (Unfortunately, you can't do this on the PIX firewalls with the version of software that we have. If you are on a PIX, please look over the shoulder of someone else.)
    1. To get into configuration mode, type the config terminal command.
    2. Now type banner motd #.
    3. Type in a mean sounding message that will scare away a hacker and end it with #.
    4. Exit out of configuration mode by typing exit.
    5. Type exit again to end your session and Press Enter to get back into the device. Do you see your new banner?

Reflection

Does your network device seem to be healthy? For example, is its CPU utilization too high? Are there lots of input and output errors on the interfaces? ___________________________________________________________________________________________________________________

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Do you think your device's status is a cause for the users complaining that the network is slow? If not, where else could you focus your troubleshooting efforts? What else might be causing the users to complain? ___________________________________________________________________________________________________________________

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Why might you want to change a device's banner? ___________________________________________________________________________________________________________________

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