Hands-on Labs

To complete the labs in this section, you need at least one router (three would be best) and at least one PC running as a TFTP server. TFTP server software must be installed and running on the PC. For this lab, it is also assumed that your PC and the router(s) are connected together with a switch or hub and that all interfaces (PC NIC and router interfaces) are in the same subnet. You can alternately connect the PC directly to the router or connect the routers directly to one another (use a crossover cable in that case). Remember that the labs listed here were created for use with real routers but can easily be used with Cisco's Packet Tracer program.

Here is a list of the labs in this chapter:

Lab 5.1: Backing Up Your Router IOS

Lab 5.2: Upgrading or Restoring Your Router IOS

Lab 5.3: Backing Up the Router Configuration

Lab 5.4: Using the Cisco Discovery Protocol (CDP)

Lab 5.5: Using Telnet

Lab 5.6: Resolving Hostnames

Hands-on Lab 5.1: Backing Up Your Router IOS

1. Log into your router, and go into privileged mode by typing en or enable.
2. Make sure you can connect to the TFTP server that is on your network by pinging the IP address from the router console.
3. Type show flash to see the contents of flash memory.
4. Type show version at the router privileged-mode prompt to get the name of the IOS currently running on the router. If there is only one file in flash memory, the show flash and show version commands show the same file. Remember that the show version command shows you the file that is currently running, and the show flash command shows you all of the files in flash memory.
5. Once you know you have good Ethernet connectivity to the TFTP server and you also know the IOS filename, back up your IOS by typing copy flash tftp. This command tells the router to copy a specified file from flash memory (this is where the IOS is stored by default) to a TFTP server.
6. Enter the IP address of the TFTP server and the source IOS filename. The file is now copied and stored in the TFTP server's default directory.

Hands-on Lab 5.2: Upgrading or Restoring Your Router IOS

1. Log into your router, and go into privileged mode by typing en or enable.
2. Make sure you can connect to the TFTP server by pinging the IP address of the server from the router console.
3. Once you know you have good Ethernet connectivity to the TFTP server, issue the copy tftp flash command.
4. Confirm that the router will not function during the restore or upgrade by following the prompts provided on the router console. It is possible this prompt may not occur.
5. Enter the IP address of the TFTP server.
6. Enter the name of the IOS filename you want to restore or upgrade.
7. Confirm that you understand that the contents of flash memory will be erased if there is not enough room in flash to store the new image.
8. Watch in amazement as your IOS is deleted out of flash memory and your new IOS is copied to flash memory.

If the file that was in flash memory is deleted but the new version wasn't copied to flash memory, the router will boot from ROM monitor mode. You'll need to figure out why the copy operation did not take place.

Hands-on Lab 5.3: Backing Up the Router Configuration

1. Log into your router, and go into privileged mode by typing en or enable.
2. Ping the TFTP server to make sure you have IP connectivity.
3. From RouterB, type copy run tftp.
4. When prompted, type the IP address of the TFTP server (for example, 172.16.30.2), and press Enter.
5. By default, the router will prompt you for a filename. The hostname of the router is followed by the suffix -confg (yes, I spelled that correctly). You can use any name you want.

   Name of configuration file to write [RouterB-confg]?

   Press Enter to accept the default name.

   Write file RouterB-confg on host 172.16.30.2? [confirm]

   Press Enter to confirm.

Hands-on Lab 5.4: Using the Cisco Discovery Protocol (CDP)

1. Log into your router, and go into privileged mode by typing en or enable.
2. From the router, type sh cdp, and press Enter. You should see that CDP packets are being sent out to all active interfaces every 60 seconds and the holdtime is 180 seconds (these are the defaults).
3. To change the CDP update frequency to 90 seconds, type cdp timer 90 in global configuration mode.

   RouterC#config t
   Enter configuration commands, one per line. End with
     CNTL/Z.
   RouterC(config)#cdp timer ?
     <5-900> Rate at which CDP packets are sent (in sec)
   RouterC(config)#cdp timer 90

4. Verify that your CDP timer frequency has changed by using the command show cdp in privileged mode.

   RouterC#sh cdp
   Global CDP information:
   Sending CDP packets every 90 seconds
   Sending a holdtime value of 180 seconds

5. Now use CDP to gather information about neighbor routers. You can get the list of available commands by typing sh cdp ?.

   RouterC#sh cdp ?
     entry     Information for specific neighbor entry
     interface CDP interface status and configuration
     neighbors CDP neighbor entries
     traffic   CDP statistics
     <cr>

6. Type sh cdp int to see the interface information plus the default encapsulation used by the interface. It also shows the CDP timer information.
7. Type sh cdp entry * to see complete CDP information received from all devices.
8. Type show cdp neighbor to gather information about all connected neighbors. (You should know the specific information output by this command.)
9. Type show cdp neighbor detail. Notice that it produces the same output as show cdp entry *.

Hands-on Lab 5.5: Using Telnet

1. Log into your router, and go into privileged mode by typing en or enable.
2. From RouterA, telnet into your remote router (RouterB) by typing telnet ip_address from the command prompt. Type exit to disconnect.
3. Now type in RouterB's IP address from RouterA's command prompt. Notice that the router automatically tries to telnet to the IP address you specified. You can use the telnet command or just type in the IP address.
4. From RouterB, press Ctrl+Shift+6 and then X to return to RouterA's command prompt. Now telnet into your third router, RouterC. Press Ctrl+Shift+6 and then X to return to RouterA.
5. From RouterA, type show sessions. Notice your two sessions. You can press the number displayed to the left of the session and press Enter twice to return to that session. The asterisk shows the default session. You can press Enter twice to return to that session.
6. Go to the session for your RouterB. Type show users. This shows the console connection and the remote connection. You can use the disconnect command to clear the session or just type exit from the prompt to close your session with RouterB.
7. Go to the RouterC's console port by typing show sessions RouterA and using the connection number to return to RouterC. Type show user, and notice the connection to your first router, RouterA.
8. Type clear line 1ine_number to disconnect the Telnet session.

Hands-on Lab 5.6: Resolving Hostnames

1. Log into your router, and go into privileged mode by typing en or enable.
2. From RouterA, type todd, and press Enter at the command prompt. Notice the error you receive and the delay. The router is trying to resolve the hostname to an IP address by looking for a DNS server. You can turn this feature off by using the no ip domain-lookup command from global configuration mode.
3. To build a host table, you use the ip host command. From RouterA, add a host table entry for RouterB and RouterC by entering the following commands:

   ip host routerb ip_address
   ip host routerc ip_address

   Here is an example:

   ip host routerb 172.16.20.2
   ip host routerc 172.16.40.2

4. Test your host table by typing ping routerb from the privileged mode prompt (not the config prompt).

   RouterA#ping routerb
   Type escape sequence to abort.
   Sending 5, 100-byte ICMP Echos to 172.16.20.2, timeout
     is 2 seconds:
   !!!!!
   Success rate is 100 percent (5/5), round-trip
     min/avg/max = 4/4/4 ms

5. Test your host table by typing ping routerc.

   RouterA#ping routerc
   Type escape sequence to abort.
   Sending 5, 100-byte ICMP Echos to 172.16.40.2, timeout
    is 2 seconds:
   !!!!!
   Success rate is 100 percent (5/5), round-trip
    min/avg/max = 4/6/8 ms

6. Telnet to RouterB, and keep your session to RouterB open to RouterA by pressing Ctrl+Shift+6 and then X.
7. Telnet to RouterC by typing routerc at the command prompt.
8. Return to RouterA, and keep the session to RouterC open by pressing Ctrl+Shift+6, then X.
9. View the host table by typing show hosts and pressing Enter.

   Default domain is not set
   Name/address lookup uses domain service
   Name servers are 255.255.255.255
   Host                 Flags      Age Type  Address(es)
   routerb             (perm, OK)  0   IP   172.16.20.2
   routerc             (perm, OK)  0   IP   172.16.40.2