CCNA FAQ:Foundation Cisco IOS Operations

CCNA FAQ:Foundation Cisco IOS Operations

Q1. What is the effect of changing the configuration register?

Answer: By changing any of the values in the configuration register from its default value of 0x2102, you are altering how the router or switch operates during initialization. The last hexadecimal field in the configuration register is the boot field. This value determines whether the device boots to ROM and loads ROMmon (0x0). Values of 0x1-0xF indicate that the device parses the startup configuration in NVRAM for any boot system commands. If the third hexadecimal character in the configuration register is a 0x4, the device ignores the startup configuration in NVRAM and enters the Setup Mode dialog.

Q2. Why would a Cisco administrator use boot system commands?

Answer: The boot system commands provide flexible means of specifying from where to load an IOS. This is especially useful if you require specifying a specific IOS file to load in Flash (if multiple files exist) or on a TFTP server.

Q3. What are the memory components in a router and what purpose do they have in the booting process?

Answer: ROM contains the POST program and the bootstrap code for the initial stages of the booting process. Flash memory stores the IOS files. The configuration register is stored in NVRAM along with the startup configuration that contains any boot system commands.

Q4. What cabling and terminal settings are required for out-of-band management?

Answer: The console and AUX ports both use the rollover cable. The terminal settings should reflect the following parameters: 9600 baud, 8 data bits, no parity bits, 1 stop bit, and no flow control.

Q5. What is the significance of having User EXEC mode in addition to Privileged EXEC mode?

Answer: User EXEC is useful if you have to give access to technicians who need rights to basic verification commands. Privileged EXEC enables access to the remaining command modes, including those commands that can affect the router or switch’s operations.

Q6. What type of cable would you connect to manage your Cisco device from the COM port of your PC?
A. Cross-over cable
B. Straight-through cable
C. Patch cable
D. Rollover cable

Answer: D. The cable to connect your terminal to the Cisco device’s console or auxiliary port is a rollover cable. Answers A, B, and C are cables that are used for ethernet networking..

Q7. Which are two methods of exiting out of Setup Mode? (Choose 2.)
A. Ctrl+C
B. Ctrl+Z
C. Answer no
D. Type end

Answer: A, C. To exit out of Setup Mode, you must answer “no” to the Would you like to enter the initial configuration dialog? [yes/no] : question, or enter Ctrl+C at any prompt. Ctrl+Z and the End key are shortcuts to exit back to Privileged EXEC..

Q8. You have just been given a router that will not save its configuration. As you boot up the router, you confirm that despite saving the configurations several times, the router enters Setup Mode consistently. What might be a possible cause?
A. Flash memory is corrupt.
B. TFTP Server is down.
C. The configuration register is 0x2100.
D. The configuration register is 0x2142.

Answer: D. When the third hexadecimal character in the configuration register is a 4, the startup-config is ignored. This is a useful utility if you are doing password recovery; however, it is important that you remember to change it back to 0x2102. A is incorrect because the configuration is not stored in Flash. B is not viable because the Cisco device looks for a config on the TFTP only if the startup-config is missing. C will force the router or switch into ROMmon mode, which means the configuration never gets loaded because the IOS needs to be loaded first..

Q9. What and where are the commands that can alter the location for the bootstrap IOS process?
A. boot system command, NVRAM memory
B. boot enable command, NVRAM memory
C. boot strap command, Flash memory
D. boot system command, Flash memory

Answer: A. The boot system commands located in the startup-config in NVRAM can manually force the router or switch to boot the IOS from somewhere other than its default locations..

Q10. Assuming no boot commands, what is the default location of the IOS and what is the order of the two fallbacks?
B. Flash, TFTP then ROM
C. ROM, Flash then TFTP
D. TFTP, Flash then ROM

Answer: B. When no boot system commands are used, the bootstrap loads the first file in Flash memory. If that file is missing or corrupt, it tries to load an IOS from a TFTP server first. If there is no network connectivity or TFTP server present, the device enters ROMmon in ROM..

Q11. Which of the following is considered a typical default configuration register?
A. 0x2100
B. 0x2142
C. 0x2101
D. 0x2102

Answer: D. A normal configuration register is 0x2102. A forces the router or switch into ROMmon. B ignores the startup-config. C would load the first file in Flash; however, it is not the default configuration register..

Q12. Which of the following are in-band management EXEC methods? (Choose 2.)
C. Console
D. Telnet
E. Auxiliary

Answer: A, D. The three in-band management session methods are SSH, Telnet, and HTTP. Answers C and E are out-of-band; B is not a management session method..

Q13. Which of the following valid commands assign an IP address to an interface from Interface Configuration mode?
A. Router(config)#ip address
B. Router(config-if)#ip address
C. Router#ip address
D. Router>ip address
E. Router(config-line)#ip address

Answer: B. Without even discussing the actual configuration of the command, the question stated that it must be in Interface Configuration mode, which means the command prompt will look like Router(config-if)# or Switch(config-if)#..

Q14. If your network does not have a TFTP server and your router’s configuration was erased, what will the prompt look like when you reboot?
A. rommon 1 >
B. Router(boot)>
C. Would you like to enter the initial configuration dialog? [yes/no] :
D. The router would not be able to boot.

Answer: C. Without a TFTP for autoinstall and with the startup-config missing, the router or switch enters Setup mode, which prompts you with Would you like to enter the initial configuration dialog? [yes/no] :. Answer A is the ROMmon prompt and D is the prompt for RxBoot mode..

Q15. Which two commands will return you to Privileged EXEC? (Choose 2.)
A. Ctrl+Z
B. end
C. disable
D. Ctrl+C

Answer: A, B. Ctrl+Z and End return you to Privileged EXEC, no matter in which level of the configuration hierarchy you are. C returns you to User EXEC from Privileged EXEC mode. D is used to exit out of Setup Mode..

Q16. Which three components are located in ROM? (Choose 3.)
A. bootstrap
C. startup-config
D. IOS file
E. ROMmon
F. running-config

Answer: A, B, E. POST, bootstrap code, and ROMmon all reside in ROM. Startup-config is located in NVRAM, and running-config is located in RAM. The IOS file is typically located in Flash memory.

Q1. You type show interfaces fa0/1 and get this output:

What could the problem possibly be with this interface?
A. Speed mismatch on directly connected interfaces
B. Collisions causing CRC errors
C. Frames received are too large
D. Interference on the Ethernet cable

Answer: D. Typically we’d see the input errors and CRC statistics increase with a duplex error, but it could be another Physical layer issue such as the cable might be receiving excessive interference or the network interface cards might have a failure. Typically you can tell if it is interference when the CRC and input errors output grow but the collision counters do not, which is the case with this question.

Q2. The output of the show running-config command comes from ___________.
B. Flash
D. Firmware

Answer: C. Once the IOS is loaded and up and running, the startup-confi will be copied from NVRAM into RAM and from then on, referred to as the running-confi.

Q3. Which two of the following commands are required when configuring SSH on your router? (Choose two.)
A. enable secret password
B. exec-timeout 0 0
C. ip domain-name name
D. username name password password
E. ip ssh version 2

Answer: C, D. To confiure SSH on your router, you need to set the username command, the ip domain-name, login local, and the transport input ssh under the VTY lines and the crypto key command. However, SSH version 2 is suggested but not required.

Q4. Which command will show you whether a DTE or a DCE cable is plugged into serial 0/0 on your router’s WAN port?
A. sh int s0/0
B. sh int serial 0/0
C. show controllers s 0/0
D. show serial 0/0 controllers

Answer: C. The show controllers serial 0/0 command will show you whether either a DTE or DCE cable is connected to the interface. If it is a DCE connection, you need to add clocking with the clock rate command.

Q5. In the work area, drag the router term to its definition on the right.

User exec mode is limited to basic monitoring commands; privileged exec mode provides access to all other router commands. Specific configuration modes include thecommands that affect a specific interface or process, while global configuration mode allows commands that affect the entire system. Setup mode is where you access the interactive configuration dialog.

Q6. Using the given output, what type of interface is f0/0?

A. 10 MB
B. 100 MB
C. 1000 MB
D. 1000 MB

Answer: B. We can see that the bandwidth is 100000 Kbit, which is 100,000,000. Kbit means to add three zeros, which is 100 Mbits per second, or FastEthernet.

Q7. Which of the following commands will configure all the default VTY ports on a switch?
A. Switch#line vty 0 4
B. Switch(config)#line vty 0 4
C. Switch(config-if)#line console 0
D. Switch(config)#line vty all

Answer: B. From global confiuration mode, use the line vty 0 4 command to set all fie default VTY lines. However, you would typically always set all lines, not just the defaults.

Q8. Which of the following commands sets the privileged mode password to Cisco and encrypts the password?
A. enable secret password Cisco
B. enable secret cisco
C. enable secret Cisco
D. enable password Cisco

Answer: C. The enable secret password is case sensitive, so the second option is wrong. To set the enable secret password, use the enable secret password command from global confiuration mode. This password is automatically encrypted.

Q9. If you wanted administrators to see a message when logging into the switch, which command would you use?
A. message banner motd
B. banner message motd
C. banner motd
D. message motd

Answer: C. The typical banner is a message of the day (MOTD) and is set by using the global confiuration mode command banner MOTD.

Q10. Which of the following prompts indicates that the switch is currently in privileged mode?
A. Switch(config)#
B. Switch>
C. Switch#
D. Switch(config-if)

Answer: C. The prompts offered as options indicate the following modes:

  • Switch(config)# is global confiuration mode.
  • Switch> is user mode.
  • Switch# is privileged mode.
  • Switch(config-if)# is interface confiuration mode.

Q11. What command do you type to save the configuration stored in RAM to NVRAM?
A. Switch(config)#copy current to starting
B. Switch#copy starting to running
C. Switch(config)#copy running-config startup-config
D. Switch#copy run start

Answer: D. To copy the running-confi to NVRAM so that it will be used if the router is restarted, use the copy running-config startup-config command in privileged mode (copy run start for short).

Q12. You try to telnet into SF from router Corp and receive this message:

Which of the following sequences will address this problem correctly?
A. Corp(config)#line console 0
Corp (config-line)#password password
Corp (config-line)#login
B. SF (config)#line console 0
SF(config-line)#enable secret password
C. Corp(config)#line vty 0 4
Corp (config-line)#password password
Corp (config-line)#login
D. SF (config)#line vty 0 4
SF(config-line)#password password
Answer: D. To allow a VTY (Telnet) session into your router, you must set the VTY password. Option C is wrong because it is setting the password on the wrong router. Notice that you have to set the password before you set the login command. Remember, Cisco may have you set the password before the login command.

Q13. Which command will delete the contents of NVRAM on a switch?
A. delete NVRAM
B. delete startup-config
C. erase flash
D. erase startup-config
E. erase start

Answer: D. The erase startup-config command erases the contents of NVRAM and will put you in setup mode if the switch is restarted. Option E is wrong because you must type in the full command!

Q14. What is the problem with an interface if you type show interface g0/1 and receive the following message?
Gigabit 0/1 is administratively down, line protocol is down
A. The keepalives are different times.
B. The administrator has the interface shut down.
C. The administrator is pinging from the interface.
D. No cable is attached.

Answer: B. If an interface is shut down, the show interface command will show the interface as administratively down. (It is possible that no cable is attached, but you can’t tell that from this message.)

Q15. Which of the following commands displays the configurable parameters and statistics of all interfaces on a switch?
A. show running-config
B. show startup-config
C. show interfaces
D. show versions

Answer: C. With the show interfaces command, you can view the confiurable parameters, get statistics for the interfaces on the switch, check for input and CRC errors, and verify if the interfaces are shut down.

Q16. If you delete the contents of NVRAM and reboot the switch, what mode will you be in?
A. Privileged mode
B. Global mode
C. Setup mode
D. NVRAM loaded mode

Answer: C. If you delete the startup-confi and reload the switch, the device will automatically enter setup mode. You can also type setup from privileged mode at any time.

Q17. You type the following command into the switch and receive the following output:

Why was this error message displayed?
A. You need to be in privileged mode.
B. You cannot have a space between fastethernet and 0/1.
C. The switch does not have a Fastethernet 0/1 interface.
D. Part of the command is missing.

Answer: D. You can view the interface statistics from user mode, but the command is show interface fastethernet 0/0.

Q18. You type Switch#sh r and receive a % ambiguous command error. Why did you receive this message?
A. The command requires additional options or parameters.
B. There is more than one show command that starts with the letter r.
C. There is no show command that starts with r.
D. The command is being executed from the wrong mode.

Answer: B. The % ambiguous command error means that there is more than one possible show command that starts with r. Use a question mark to fid the correct command.

Q19. Which of the following commands will display the current IP addressing and the layer 1 and 2 status of an interface? (Choose two.)
A. show version
B. show interfaces
C. show controllers
D. show ip interface
E. show running-config

Answer: B, D. The commands show interfaces and show ip interface will show you the layer 1 and 2 status and the IP addresses of your router’s interfaces.

Q20. At which layer of the OSI model would you assume the problem is if you type show interface serial 1 and receive the following message?
Serial1 is down, line protocol is down
A. Physical layer
B. Data Link layer
C. Network layer
D. None; it is a router problem.

Answer: A. If you see that a serial interface and the protocol are both down, then you have a Physical layer problem. If you see serial1 is up, line protocol is down, then you are not receiving (Data Link) keepalives from the remote end.
CCNA Frequently Asked Questions CCNA Exam Questions with Explanation


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