Table Of Content259
Using Telnet for Remote Administration
NY-R1>resume 1
[Resuming connection 1 to 24.0.0.2 ... ]
BOS-R1>
Figure 3-10:
The show
sessions
command
displays any
suspended Book II
Telnet Chapter 3
sessions
that you can
M
reconnect a
n
to. Da
eg
vicing
es C
is
c
When the router displays the resuming connection message, press the Enter o
key to activate the connection.
When you use the show sessions command and you see a suspended
session that you have forgotten about and no longer need, you can
disconnect from that session without resuming it by using the disconnect
command and specifying the connection number, as shown in Figure 3-11.
Figure 3-11:
You can
close a
suspended
Telnet
session
with the
disconnect
command.
If you are currently in the Telnet session, you can type exit to close the
Telnet session, but if you have suspended the Telnet session and are not
currently in it, you need to use the disconnect command.
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260
Chapter Summary
Monitoring connections
As a router administrator, you want to keep a close eye on who is connected
to the router. The show users command displays any connections to the
router, including Telnet and local connections, using the console port. In
Figure 3-12, you (as the router administrator) can see two connections to
router BOS-R1; one is at the console, and the other is a Telnet session
(displayed with vty).
Figure 3-12:
You can
monitor
connections
to the Cisco
router
with the
show users
command.
Chapter Summary
This chapter introduces you to a number of concepts that are important to
managing Cisco devices. The following are some key points to remember for
the CCENT certification exam:
✦ You back up your router configuration to a TFTP server using the copy
running-config tftp command.
✦ You back up your IOS to a TFTP server using the copy flash tftp
command.
✦ You upgrade your IOS using the copy tftp flash command.
✦ You use the boot system flash command to specify a particular IOS
file in flash memory that you want to use when the router boots up.
✦ CDP is a Cisco protocol that can help you discover neighboring devices
and information about them.
✦ The show cdp neighbors command shows you a list of neighboring
devices, while the show cdp entry command displays information
about a specific device. You can view detailed information about all
neighboring devices with the show cdp neighbors detail command.
✦ You disable CDP on your Cisco router by using the no cdp run
command. You can also disable CDP on a specific interface by using the
no cdp enable command at an interface prompt.
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261
Lab Exercises
✦ You Telnet into another Cisco device using the telnet command. Once
you Telnet into another device, you can suspend that connection by
using the Ctrl-Shift-6 keystroke and then pressing X.
✦ You can view a list of suspended Telnet sessions using the show
sessions command, and you can then reconnect to a session using the
resume command.
✦ In order to Telnet into a Cisco device, the Cisco device must have a
password assigned to the Telnet (vty) ports, and it must have an enable
password or enable secret.
Lab Exercises Book II
Chapter 3
This chapter introduces you to concepts related to managing Cisco devices.
You discover how to back up and restore your configuration and IOS to M
a TFTP server. You also find out how to use CDP to discover information an
Da
about a Cisco device and how to Telnet into a device. The following labs eg
help you get familiar with backing up and restoring your configuration, vicing
working with CDP, and using Telnet. es Cis
c
o
These labs build off of each other, so be sure to complete the labs in order.
Lab 3-1: Backing up and restoring
your configuration
In this lab, you install a TFTP server on your system and then back up your
router configuration to the TFTP server. You end the lab by restoring the
configuration back to your router.
To install and configure your own TFTP server, follow these steps on a
Windows computer on your test lab network:
1. Download a trial version of WinAgents TFTP Server software from
www.tftp-server.com.
2. Run the downloaded executable (most likely tftpserver-setup.
exe) by double-clicking the executable.
3. When the welcome screen displays, click Next.
4. Select the I Accept the License Agreement option and click Next.
5. On the Select Installation Type screen, select Complete, and then
click Next.
6. Click Next to accept the Windows Firewall options.
7. Click Next to begin the installation.
8. When the installation completes, click Finish.
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262
Lab Exercises
9. To start the TFTP server, choose Start➪All Programs➪WinAgents
TFTP Server 4➪TFTP Server Manager.
10. Choose to connect to the local server (your system) and click OK.
11. Click Yes to start the service.
12. Leave the TFTP Server Manager window open.
13. Now that you have the TFTP server installed, you can back up your
router configuration to the TFTP server. Connect to the router with
HyperTerminal and type the following command:
router#copy running-config tftp
14. Answer the questions by supplying your computer’s IP address as the
IP address of the TFTP server, and create a destination file named
lab3_1_confg.
15. When the backup completes, change the name of your router with the
following command:
router#config term
router(config)#hostname Rout_back
16. Test a restore of the configuration on the TFTP server by typing the
following command:
Rout_back(config)#exit
Rout_back#copy tftp running-config
17. When prompted for the IP address of the TFTP server, supply the IP
address of your computer running the TFTP server software and
specify that the file to download is lab3_1_confg.
18. After the copy command is complete, you should notice that your
router name is back to the original router name; the router name
should now be router#.
Lab 3-2: Using CDP to discover the network
In this lab, use CDP to discover other Cisco devices on the network. For this
lab, you need to ensure that you have a router connected to other devices,
such as another router and a switch.
1. Console into the router from HyperTerminal, if you are not connected
to the router already.
2. From priv exec mode, use the show cdp neighbors command to
view a list of devices connected directly to your router:
router>enable
router#show cdp neighbors
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263
Lab Exercises
As you view the list of devices, answer the following questions:
a. Do you see the neighboring router?
b. What is the device ID of the router?
c. What is the platform of the router?
d. Do you see the neighboring switch?
e. What is the device ID of the switch?
f. What is the platform of the switch?
Notice in the output of the show cdp neighbors command that you
do not know the IP address of these devices. Book II
Chapter 3
3. To find out the IP addresses of the devices, use the following command:
router#show cdp neighbors detail
M
a
As you view the IP addresses of the devices, answer the following n
Da
questions: eg
vicing
a. What is the IP address of the router? es C
is
c
b. What is the IP address of the switch? o
Lab 3-3: Using Telnet for remote administration
Now that you have the IP address of your neighboring Cisco devices, Telnet
into the device so you can change the hostname of that router to router2.
1. Console into the router from HyperTerminal, if you are not connected
to the router already.
2. To Telnet into your neighboring router, type this:
telnet <ip_of_neighboring_router>
3. Once you Telnet into the router, change the hostname of the router to
router2:
router>enable
router#config term
router(config)#hostname router2
router2(config)#
4. Suspend the Telnet session by using the Ctrl-Shift-6, then X, key
sequence.
You are now back on your original router.
5. To display a list of disconnected sessions, use the show sessions
command.
6. Write down the session ID of your last session.
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264
Lab Exercises
7. Reconnect to the session you recorded in Step 6 by using the resume
<ID> command.
You should be on the second router now.
8. End the Telnet session by typing exit.
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Prep Test M
a
n
1 What is the command to back up your running configuration to a TFTP server? a
A ❍ backup running-config tftp g
B ❍ copy running-config tftp i
n
C ❍ backup tftp running-config
g
D ❍ copy tftp running-config
2 C
What is the command to back up your IOS to a TFTP server?
i
A ❍ backup flash tftp
s
B ❍ copy tftp flash c
C ❍ backup tftp flash o
D ❍ copy flash tftp
D
3
You need to identify other Cisco devices on the network; which Cisco protocol
e
do you use?
v
A ❍ Spanning Tree Protocol
i
B ❍ Point-to-Point Protocol c
C ❍ Cisco Discovery Protocol e
D ❍ Discovery Device Protocol s
4
You wish to view only the IP addresses of neighboring devices; what command
do you use?
A ❍ show cdp entry * protocol
B ❍ show cdp neighbors
C ❍ show cdp neighbors detail
D ❍ show cdp
5
How do you suspend your Telnet session?
A ❍ suspend
B ❍ pause
C ❍ Ctrl-Shift-6, then X
D ❍ Ctrl-Alt-Del
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s
6
You have suspended a Telnet session and wish to reconnect to that session
e
again; what command do you use?
c
i A ❍ reconnect <IP Address>
v B ❍ resume <Device ID>
e C ❍ reconnect <Device ID>
D D ❍ resume <IP Address>
7
o What command do you use to determine if you have any suspended Telnet
c sessions?
s A ❍ show sessions
i B ❍ show users
C
C ❍ show suspensions
D ❍ show suspended users
g
n 8
What command do you use to disable CDP on the serial interface?
i
g A ❍ disable cdp
B ❍ cdp disable
a
C ❍ no disable cdp
n
D ❍ no cdp enable
a
M 9 What command do you use to determine the model number of a switch called
NY-SW1?
A ❍ show cdp entry NY-SW1
B ❍ show cdp
C ❍ show cdp NY-SW1
D ❍ show cdp protocol NY-SW1
10
You wish to disable CDP on your router; what command co you use?
A ❍ disable cdp
B ❍ no cdp run
C ❍ no cdp enable
D ❍ no disable cdp
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Answers M
a
n
1 B. In order to back up your configuration, such as the running-config, or your
a
IOS, you can use the copy <source> <destination> command. See
“Backing up your configuration.” g
2 D. The copy command backs up the Cisco IOS. Because the IOS resides in flash i
n
memory and you are sending the copy to the TFTP server, you need to use the
copy flash tftp syntax. Review “Backing up your IOS.” g
3 C. The Cisco Discovery Protocol (CDP) identifies neighboring Cisco devices and
C
gives you information about each device, such as its platform and IP address.
Check out “CDP overview.” i
s
4 A. The show cdp entry * protocol command shows all devices, and only c
the IP address of the devices. You can use the show cdp neighbors detail
o
command to view all devices and their IP addresses, but you receive more
information than just the IP address (which makes this an incorrect choice). D
Peruse “The show cdp entry command.”
e
5 C. You can temporarily suspend a Telnet session with the Ctrl-Shift-6, and then
v
X keystroke. Take a look at “Suspending and disconnecting a session.”
i
6 B. In order to resume a suspended Telnet session, you use the resume c
command and specify the device ID as a parameter. Peek at “Suspending and e
disconnecting a session.”
s
7 A. The show sessions command displays a list of suspended Telnet sessions.
Look over “Suspending and disconnecting a session.”
8 D. To disable CDP on an interface, you need to navigate to that interface and use
the no cdp enable command. Study “Disabling CDP on an interface.”
9 A. To display details about a specific neighboring device, use the show cdp
entry command with the device ID. This displays information about the device,
such as the device ID, IP address, and the platform (model). Refer to “The show
cdp entry command.”
10 B. To disable CDP on the router and not just on an interface, use the no cdp
run command. Examine “Disabling CDP globally.”
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268
Book II: Cisco Device Basics
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