Senior Acquisitions Editor: Kenyon Brown Development Editor: Kim Wimpsett

Build a static host table on a router. By using the global

configuration command

ip host

host_name ip_address

, you can build a

static host table on your router. You can apply multiple IP addresses

against the same host entry.

Verify the host table on a router. You can verify the host table with

the

show hosts

command.

Describe the function of the

ping

command. Packet Internet Groper

(

ping

) uses ICMP echo requests and ICMP echo replies to verify an active

IP address on a network.

Ping a valid host ID from the correct prompt. You can ping an IP

address from a router’s user mode or privileged mode but not from

configuration mode, unless you use the

do

​command. You must ping a

valid address, such as 1.1.1.1.

Written Labs 7

In this section, you’ll complete the following labs to make sure you’ve got

the information and concepts contained within them fully dialed in:

Lab 7.1: IOS Management

Lab 7.2: Router Memory

You can find the answers to these labs in Appendix A, “Answers to

Written Labs.”

Written Lab 7.1: IOS Management

Write the answers to the following questions:

1.  What is the command to copy the startup-config file to DRAM?

2.  What command can you use to see the neighbor router’s IP address

from your router prompt?

3.  What command can you use to see the hostname, local interface,

platform, and remote port of a neighbor router?

4.  What keystrokes can you use to telnet into multiple devices

simultaneously?

5.  What command will show you your active Telnet connections to

neighbor and remote devices?

6.  What command can you use to merge a backup configuration with the

configuration in RAM?

7.  What protocol can be used on a network to synchronize clock and date

information?

8.  What command is used by a router to forward a DHCP client request

to a remote DHCP server?

9.  What command enables your switch or router to receive clock and

date information and synchronize with the NTP server?

10.  Which NTP verification command will show the reference master for

the client?

Written Lab 7.2: Router Memory

Identify the location in a router where each of the following files is stored

by default.

1.  Cisco IOS

2.  Bootstrap

3.  Startup configuration

4.  POST routine

5.  Running configuration

6.  ARP cache

7.  Mini-IOS

8.  ROM Monitor

9.  Routing tables

10.  Packet buffers

Hands-on Labs

To complete the labs in this section, you need at least one router or switch

(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 Cisco devices are connected together

with a switch 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 the LammleSim IOS Version (see

www.lammle.com/ccna

) or you can use the Cisco Packet Tracer router

simulator. Last, although it doesn’t matter if you are using a switch or

router in these labs, I’m just going to use my routers, but feel free to use

your switch to go through these labs!

Here is a list of the labs in this chapter:

Lab 7.1: Backing Up the Router Configuration

Lab 7.2: Using the Cisco Discovery Protocol (CDP)

Lab 7.3: Using Telnet

Lab 7.4: Resolving Hostnames

Hands-on Lab 7.1: Backing Up the Router Configuration

In this lab, you’ll back 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 7.2: Using the Cisco Discovery Protocol

(CDP)

CDP is an important objective for the Cisco exams. Please go through this

lab and use CDP as much as possible during your studies.

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.

Router#

config t

Enter configuration commands, one per line. End with

CNTL/Z.

Router(config)#

cdp timer ?

<5-900> Rate at which CDP packets are sent (in sec)

Router(config)#

cdp timer 90

4.  Verify that your CDP timer frequency has changed by using the

command

show cdp

in privileged mode.

Router#

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 ?

.

Router#

sh cdp ?

entry Information for specific neighbor entry

interface CDP interface status and configuration

neighbors CDP neighbor entries

traffic CDP statistics

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 neighbors

to gather information about all connected

neighbors. (You should know the specific information output by this

command.)

9.  Type

show cdp neighbors detail

. Notice that it produces the same

output as

show cdp entry *

.

Hands-on Lab 7.3: Using Telnet

Secure Shell was covered in Chapter 6, and it is what you should use for

remote access into a Cisco device. However, the Cisco objectives cover

Telnet configuration, so let’s do a lab on 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

telnetip_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 RouterC’s console port by typing

show sessions

on the first

router 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

line_number

to disconnect the Telnet session.

Hands-on Lab 7.4: Resolving Hostnames

It’s best to use a DNS server for name resolution, but you can also create

a local hosts table to resolve names. Let’s take a look.

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 routerbip_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, 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

Review Questions

The following questions are designed to test your

understanding of this chapter’s material. For more information on

how to get additional questions, please see

www.lammle.com/ccna

.

You can find the answers to these questions in Appendix B, “Answers to

Review Questions.”

1.  Which of the following is a standards-based protocol that provides

dynamic network discovery?

A.  DHCP

B.  LLDP

C.  DDNS

D.  SSTP

E.  CDP

2.  Which command can be used to determine a router’s CPU utilization?

A.

show version

B.

show controllers

C.

show processes cpu

D.

show memory

3.  You are troubleshooting a connectivity problem in your corporate

network and want to isolate the problem. You suspect that a router on

the route to an unreachable network is at fault. What IOS

user exec

command should you issue?

A.

Router>ping

B.

Router>trace

C.

Router>show ip route

D.

Router>show interface

E.

Router>show cdp neighbors

4.  You copy a configuration from a network host to a router’s RAM. The

configuration looks correct, yet it is not working at all. What could the

problem be?

A.  You copied the wrong configuration into RAM.

B.  You copied the configuration into flash memory instead.

C.  The copy did not override the

shutdown

command in running-

config.

D.  The IOS became corrupted after the

copy

command was initiated.

5.  In the following command, what does the IP address 10.10.10.254

refer to?

Router#

config t

Router(config)#

interface fa0/0

Router(config-if)#

ip helper-address 10.10.10.254

A.  IP address of the ingress interface on the router

B.  IP address of the egress interface on the router

C.  IP address of the next hop on the path to the DHCP server

D.  IP address of the DHCP server

6.  The corporate office sends you a new router to connect, but upon

connecting the console cable, you see that there is already a

configuration on the router. What should be done before a new

configuration is entered in the router?

A.  RAM should be erased and the router restarted.

B.  Flash should be erased and the router restarted.

C.  NVRAM should be erased and the router restarted.

D.  The new configuration should be entered and saved.

7.  What command can you use to determine the IP address of a directly

connected neighbor?

A.

show cdp

B.

show cdp neighbors

C.

show cdp neighbors detail

D.

show neighbor detail

8.  According to the output, what interface does SW-2 use to connect to

SW-3?

SW-3#

sh cdp neighbors

Capability Codes: R - Router, T - Trans Bridge, B - Source Route

BridgeS - Switch, H - Host, I - IGMP, r - Repeater, P - Phone, D

- Remote, C - CVTA, M - Two-port Mac Relay Device ID

Local Intrfce Holdtme Capability Platform Port ID

SW-1 Fas 0/1 170 S I WS-C3560- Fas 0/15

SW-1 Fas 0/2 170 S I WS-C3560- Fas 0/16

SW-2 Fas 0/5 162 S I WS-C3560- Fas 0/2

A.  Fas 0/1

B.  Fas 0/16

C.  Fas 0/2

D.  Fas 0/5

9.  Which of the following commands enables syslog on a Cisco device

with

debugging

as the level?

A.

syslog 172.16.10.1

B.

logging 172.16.10.1

C.

remote console 172.16.10.1 syslog debugging

D.

transmit console messages level 7 172.16.10.1

10.  You save the configuration on a router with the

copy running-config

startup-config

command and reboot the router. The router, however,

comes up with a blank configuration. What can the problem be?

A.  You didn’t boot the router with the correct command.

B.  NVRAM is corrupted.

C.  The configuration register setting is incorrect.

D.  The newly upgraded IOS is not compatible with the hardware of

the router.

E.  The configuration you saved is not compatible with the hardware.

11.  If you want to have more than one Telnet session open at the same

time, what keystroke combination would you use?

A.  Tab+spacebar

B.  Ctrl+X, then 6

C.  Ctrl+Shift+X, then 6

D.  Ctrl+Shift+6, then X

12.  You are unsuccessful in telnetting into a remote device from your

switch, but you could telnet to the router earlier. However, you can

still ping the remote device. What could the problem be? (Choose

two.)

A.  IP addresses are incorrect.

B.  Access control list is filtering Telnet.

C.  There is a defective serial cable.

D.  The VTY password is missing.

13.  What information is displayed by the

show hosts

command? (Choose

two.)

A.  Temporary DNS entries

B.  The names of the routers created using the

hostname

command

C.  The IP addresses of workstations allowed to access the router

D.  Permanent name-to-address mappings created using the

ip host

command

E.  The length of time a host has been connected to the router via

Telnet

14.  Which three commands can be used to check LAN connectivity

problems on an enterprise switch? (Choose three.)

A.

show interfaces

B.

show ip route

C.

tracert

D.

ping

E.

dns lookups

15.  What is the default syslog facility level?

A.  local4

B.  local5

C.  local6

D.  local7

16.  You telnet into a remote device and type

debug ip icmp

, but no output

from the

debug

command is seen. What could the problem be?

A.  You must type the

show ip icmp

command first.

B.  IP addressing on the network is incorrect.

C.  You must use the

terminal monitor

command.

D.  Debug output is sent only to the console.

17.  Which three statements about syslog utilization are true? (Choose

three.)

A.  Utilizing syslog improves network performance.

B.  The syslog server automatically notifies the network administrator

of network problems.

C.  A syslog server provides the storage space necessary to store log

files without using router disk space.

D.  There are more syslog messages available within Cisco IOS than

there are comparable SNMP trap messages.

E.  Enabling syslog on a router automatically enables NTP for

accurate time stamping.

F.  A syslog server helps in aggregation of logs and alerts.

18.  You need to gather the IP address of a remote switch that is located in

Hawaii. What can you do to find the address?

A.  Fly to Hawaii, console into the switch, then relax and have a drink

with an umbrella in it.

B.  Issue the

show ip route

command on the router connected to the

switch.

C.  Issue the

show cdp neighbor

command on the router connected to

the switch.

D.  Issue the

show ip arp

command on the router connected to the

switch.

E.  Issue the

show cdp neighbors detail

command on the router

connected to the switch.

19.  You need to configure all your routers and switches so they

synchronize their clocks from one time source. What command will

you type for each device?

A.

clock synchronization

ip_address

B.

ntp master ip_address

C.

sync ntp ip_address

D.

ntp server

ip_address version

number

20.  A network administrator enters the following command on a router:

logging trap 3

. What are three message types that will be sent to the

syslog server? (Choose three.)

A.  Informational

B.  Emergency

C.  Warning

D.  Critical

E.  Debug

F.  Error

Chapter 8

Managing Cisco Devices

The following ICND1 exam topics are covered in

this chapter:

x5.0 Infrastructure Management

5.2 Configure and verify device management

5.2.c Licensing

5.5 Perform device maintenance

5.5.a Cisco IOS upgrades and recovery (SCP, FTP, TFTP, and

MD5 verify)

5.5.b Password recovery and configuration register

5.5.c File system management

Here in Chapter 8, I’m going to show you how

to ​manage Cisco routers on an internetwork. The Internetwork Operating

System (IOS) and configuration files reside in ​different locations in a

Cisco device, so it’s really important to understand both where these files

are located and how they work.

You’ll be learning about the configuration register, including how to use

the ​configuration register for password recovery.

Finally, I’ll cover how to verify licenses on the ISRG2 routers as well as

how to install a permanent license and configure evaluation features in

the latest universal images.

To find up-to-the-minute updates for this chapter, please see

www.lammle.com/ccna

or the book's web page at

www.sybex.com/go/ccna

.

Managing the Configuration Register

All Cisco routers have a 16-bit software register that’s written into

NVRAM. By default, the configuration register is set to load the Cisco

IOS from flash memory and to look for and load the startup-config file

from NVRAM. In the following sections, I am going to ​discuss the

configuration register settings and how to use these settings to provide

password recovery on your routers.

Understanding the Configuration Register Bits

The 16 bits (2 bytes) of the configuration register are read from 15 to 0,

from left to right. The default configuration setting on Cisco routers is

0x2102. This means that bits 13, 8, and 1 are on, as shown in

Table 8.1

.

Notice that each set of 4 bits (called a nibble) is read in binary with a

value of 8, 4, 2, 1.