Chapter 6 - Cisco’s Internetworking Operating System (IOS)

Question 1

List the options available to connect to a Cisco device for management purposes.

Answer 1

The three options available are the console port, auxiliary port, and in-band communication, such as Telnet, SSH and HTTP. Don’t forget, a Telnet connection is not possible until an IP address has been configured and a Telnet password has been configured.

Question 2

Understand the boot sequence of a router.

Answer 2

When you first bring up a Cisco router, it will run a power-on self-test (POST), and if that passes, it will look for and load the Cisco IOS from flash memory, if a file is present. The IOS then proceeds to load and looks for a valid configuration in NVRAM called the startup-config. If no file is present in NVRAM, the router will go into setup mode.

Question 3

Describe the use of setup mode.

Answer 3

Setup mode is automatically started if a router boots and no startup-config is in NVRAM. You can also bring up setup mode by typing setup from privileged mode. Setup provides a minimum amount of configuration in an easy format for someone who does not understand how to configure a Cisco router from the command line.

Question 4

Differentiate user, privileged, and global configuration modes, both visually and from a command capabilities perspective.

Answer 4

User mode, indicated by the routername > prompt, provides a command-line interface with very few available commands by default. User mode does not allow the configuration to be viewed or changed. Privileged mode, indicated by the routername# prompt, allows a user to both view and change the configuration of a router. You can enter privileged mode by typing the command enable and entering the enable password or enable secret password, if set. Global configuration mode, indicated by the routername( config)# prompt, allows configuration changes to be made that apply to the entire router (as opposed to a configuration change that might affect only one interface, for example).n.

Question 5

Recognize additional prompts available in other modes and describe their use.

Answer 5

Additional modes are reached via the global configuration prompt, routername( config)#, and their prompts include interface, router( config-if)#, for making interface settings; line configuration mode, router( config-line)#, used to set passwords and make other settings to various connection methods; and routing protocol modes for various routing protocols, router( config-router)#, used to enable and configure routing protocols.

Question 6

Access and utilize editing and help features.

Answer 6

Make use of typing a question mark at the end of commands for help in using the commands. Additionally, understand how to filter command help with the same question mark and letters. Use the command history to retrieve commands previously utilized without retyping. Understand the meaning of the caret when an incorrect command is rejected. Finally, identify useful hot key combinations.

Question 7

Identify the information provided by the show version command.

Answer 7

The show version command will provide basic configuration for the system hardware as well as the software version, the names and sources of configuration files, the configuration register setting, and the boot images.

Question 8

Set the hostname of a router.

Answer 8

The command sequence to set the hostname of a router is as follows:
enable
config t
hostname Todd

Question 9

Differentiate the enable password and enable secret password.

Answer 9

Both of these passwords are used to gain access into privileged mode. However, the enable secret password is newer and is always encrypted by default. Also, if you set the enable password and then set the enable secret, only the enable secret will be used.

Question 10

Describe the configuration and use of banners.

Answer 10

Banners provide information to users accessing the device and can be displayed at various login prompts. They are configured with the banner command and a keyword describing the specific type of banner.

Question 11

Set the enable secret on a router.

Answer 11

To set the enable secret, you use the global config command enable secret. Do not use enable secret password password or you will set your password to password password. Here is an example:
enable
config t
enable secret todd

Question 12

Set the console password on a router.

Answer 12

To set the console password, use the following sequence: 
enable 
config t 
line console 0
password todd
login

Question 13

Set the Telnet password on a router.

Answer 13

To set the Telnet password, the sequence is as follows:
 enable 
config t 
line vty 0 4 
password todd 
login

Question 14

Describe the advantages of using Secure Shell and list its requirements.

Answer 14

Secure Shell (SSH) uses encrypted keys to send data so that usernames and passwords are not sent in the clear. It requires that a hostname and domain name be configured and that encryption keys be generated.

Question 15

Describe the process of preparing an interface for use.

Answer 15

To use an interface, you must configure it with an IP address and subnet mask in the same subnet of the hosts that will be connecting to the switch that is connected to that interface. It also must be enabled with the no shutdown command. A serial interface that is connected back to back with another router serial interface must also be configured with a clock rate on the DCE end of the serial cable.

Question 16

Understand how to troubleshoot a serial link problem.

Answer 16

If you type show interface serial 0/ 0 and see down, line protocol is down, this will be considered a Physical layer problem. If you see it as up, line protocol is down, then you have a Data Link layer problem.

Question 17

Understand how to verify your router with the show interfaces command.

Answer 17

If you type show interfaces, you can view the statistics for the interfaces on the router, verify whether the interfaces are shut down, and see the IP address of each interface.

Question 18

Describe how to view, edit, delete, and save a configuration.

Answer 18

The show running-config command is used to view the current configuration being used by the router. The show startup-config command displays the last configuration that was saved and is the one that will be used at next startup. The copy running-config startup-config command is used to save changes made to the running configuration in NVRAM. The erase startup-config command deletes the saved configuration and will result in the invocation of the setup menu when the router is rebooted because there will be no configuration present.

Question 19

What command is used to set a serial interface to provide clocking to another router at 1000 Kb?

Answer 19

Router (config)# clock rate 10000000

Question 20

If you telnet into a switch and get the response connection refused, password not set, what commands would you execute on the destination device to stop receiving this message and not be prompted for a password?

Answer 20

Switch# config t
Switch (config)# line vty 0 15
Switch (config-line)# no login

Question 21

If you type show int fastethernet 0/ 1 and notice the port is administratively down, what commands would you execute to enable the interface?

Answer 21

Switch# config t
Switch (config)# int f0/1
Switch (config-if)# no shutdown

Question 22

If you wanted to delete the configuration stored in NVRAM, what command( s) would you type?

Answer 22

Switch# erase startup-config

Question 23

If you wanted to set the user-mode password to todd for the console port, what command( s) would you type?

Answer 23

Switch# config t
Switch (config)# line console 0
Switch (config)# password todd
Switch (config)# login

Question 24

If you wanted to set the enable secret password to cisco, what command( s) would you type?

Answer 24

Switch# config t

Switch (config)# enable secret cisco

Question 25

If you wanted to determine if serial interface 0/ 2 on your router should provide clocking, what command would you use?

Answer 25

Router# show controllers serial 0/2

Question 26

What command would you use to see the terminal history size?

Answer 26

Switch# show terminal

Question 27

You want to reinitialize the switch and totally replace the running-config with the current startup-config. What command will you use?

Answer 27

Switch# reload

Question 28

How would you set the name of a switch to Sales?

Answer 28

Switch# config t

Switch (config)# hostname Sales