TCP/IP Model & Operation Questions

Here you will find answers to TCP/IP Model & Operation Questions

Question 1

An inbound access list has been configured on a serial interface to deny packet entry for TCP and UDP ports 21, 23 and 25. What types of packets will be permitted by this ACL? (Choose three)

A. FTP
B. Telnet
C. SMTP
D. DNS
E. HTTP
F. POP3

Answer: D E F

Explanation

The access list denies packet entry for TCP & UDP -> all the services on ports 21, 23 and 25 are disabled. Services on these ports are FTP (port 21), Telnet (port 23), SMTP (port 25). Other services are allowed so D E F are the correct answers.

Question 2

What are two characteristics of Telnet? (Choose two)

A. It sends data in clear text format.
B. It is no longer supported on Cisco network devices.
C. It is more secure than SSH.
D. It requires an enterprise license in order to be implemented.
E. It requires that the destination device be configured to support Telnet connections.

Answer: A E

Explanation

Telnet, part of the TCP/IP protocol suite, is a virtual terminal protocol that allows you to make connections to remote devices, gather information, and run programs. Telnet is considered insecure because it transfers all data in clear text -> A is correct.

The destination device needs to support Telnet connection. For example, if a device doesn’t support TCP/IP protocol suit then maybe we can’t telnet to it.

Question 3

An administrator issues the command ping 127.0.0.1 from the command line prompt on a PC. If a reply is received, what does this confirm?

A. The PC has connectivity with a local host.
B. The PC has connectivity with a Layer 3 device.
C. The PC has a default gateway correctly configured
D. The PC has connectivity up to Layer 5 of the OSI model
E. The PC has the TCP/IP protocol stack correctly installed.

Answer: E

Explanation

The address 127.0.0.1 is called loopback address. When we ping 127.0.0.1, in fact we are pinging the local network card and test the TCP/IP protocol suite on our device.

Question 4

Where does routing occur within the DoD TCP/IP reference model?

A. application
B. internet
C. network
D. transport

Answer: B

Explanation

The picture below shows the comparison between TCP/IP model & OSI model. Notice that the Internet Layer of TCP/IP is equivalent to the Network Layer which is responsible for routing decision.

Question 5

A host is attempting to send data to another host on a different network. What is the first action that the sending host will take?

A. Drop the data.
B. Send the data frames to the default gateway.
C. Create an ARP request to get a MAC address for the receiving host.
D. Send a TCP SYN and wait for the SYN ACK with the IP address of the receiving host.

Answer: B

Explanation

Before sending data, the sending host checks if the destination host is inside or outside the local network. If it is outside the local network, the data will be sent to the default gateway.

Question 6

A TCP/IP Transfer is diagrammed in the exhibit.
A window size of three has been negotiated for this transfer. Which message will be returned from the receiver to the sender as part of this TCP/IP transfer?

A. Send ACK 1-3
B. Send ACK 3
C. Send ACK 4
D. Send ACK 4-6
E. Send ACK 6
F. Send ACK 7

Answer: C

Explanation

In response, the receiver replies with an ACK. The acknowledgment number is set to one more than the received sequence number. The ACK means “I have got all messages up to sequence number n-1 so please send me the message for sequence number n”.

Question 7

What is the purpose using the traceroute command?

A. to map all the devices on a network.
B. to display the current TCP/IP configuration values.
C. to see how a device MAC address is mapped to its IP address.
D. to see the path a packet will take when traveling to a specified destination.
E. to display the MTU values for each router in a specified network path from source to a destination.

Answer: D

Question 8

A network admin wants to know every hop the packets take when he accesses cisco.com. Which command is the most appropriate to use?

A. path cisco.com
B. debugcisco.com
C. trace cisco.com
D. traceroute cisco.com

Answer: D

Question 9

Refer to the exhibit. Host A pings Host B. What source MAC address and source IP address are contained in the frame as the frame leaves R2 destined for host B?

A. abcd.abcd.a001
B. abcd.abcd.b002
C. abcd.abcd.c003
D. 10.2.0.15
E. 10.0.64.1
F. 10.0.128.15

Answer: B D

Explanation

When packets are sent from Host A to Host B, the source and destination IP addresses are never changed and they are the IP addresses of Host A & Host B. Only the MAC addresses will be changed to reflect the device of the current network. In this case, when the frame leaves R2 destined for host B. It will have:

+ Source IP: IP of Host A - 10.2.0.15 (never changed)
+ Destination IP: IP of Host B – 10.0.128.15 (never changed)
+ Source MAC: MAC of Fa0/0 of R2 – abcd.abcd.b002
+ Destination MAC: MAC of Host B – abcd.abcd.d004

Question 10

Host 1 is trying to communicate with Host 2. The e0 interface on Router C is down. Which of the following are true? (Choose two)

A. Router C will use ICMP to inform Host 1 that Host 2 cannot be reached.
B. Router C will use ICMP to inform Router B that Host 2 cannot be reached.
C. Router C will use ICMP to inform Host 1, Router A, and Router B that Host 2 cannot be reached.
D. Router C will send a Destination Unreachable message type.
E. Router C will send a Router Selection message type.
F. Router C will send a Source Quench message type.

Answer: A D

Explanation

The last known good router will try to inform you that the destination cannot be reached (with a Destination Unreachable message type) so from that information you can learn how far your packets can travel to and where the problem is.

Question 11

Refer to the exhibit. The switch in the graphic has a default configuration and the MAC table is fully populated. In addition, this network is operating properly. The graphic represents selected header information in a frame leaving host A. What can be concluded from this information?

A. The MAC address of host A is FFFF.FFFF.FFFF.
B. The router will forward the packet in this frame to the Internet.
C. The switch will only forward this frame to the attached router interface.
D. All devices in this LAN except host A will pass the packet to Layer 3.

Answer: D

Explanation

This frame is leaving host A so host A is the source of this frame. In this frame, the MAC destination is FFFF.FFFF.FFFF which is a broadcast address so Sw1 will flood this frame out all its ports except the port it received the frame -> Hosts B, C, D and the interface connected to Sw1 on R1 will receive this frame. When receiving this frame, they will pass the packet to Layer 3 (because they consider broadcast address “everyone, including me”). At Layer 3, the Destination IP will be checked and only the host (or the interface on the router) with correct IP will respond to Host A while others keep silence -> D is correct.

Just for your information, maybe you can ask “this is a broadcast message so why router R1 doesn’t drop it?”. Suppose this is an ARP Request message. In fact, R1 drops that packet but it also learns that it is an ARP Request so R1 looks up its routing table to find a route to that destination. If it can find one, it will send an ARP Reply back for host A”.

OSI Questions

Here you will find answers to OSI Questions

Note: If you are not sure about OSI Model, please read my OSI tutorial.

Question 1

Which of the following correctly describe steps in the OSI data encapsulation process? (Choose two)

A. The transport layer divides a data stream into segments and may add reliability and flow control information.
B. The data link layer adds physical source and destination addresses and an FCS to the segment.
C. Packets are created when the network layer encapsulates a frame with source and destination host addresses and protocol-related control information.
D. Packets are created when the network layer adds Layer 3 addresses and control information to a segment.
E. The presentation layer translates bits into voltages for transmission across the physical link.

Answer: A D

Explanation

The transport layer segments data into smaller pieces for transport. Each segment is assigned a sequence number, so that the receiving device can reassemble the data on arrival.

The transport layer also use flow control to maximize the transfer rate while minimizing the requirements to retransmit. For example, in TCP, basic flow control is implemented by acknowledgment by the receiver of the receipt of data; the sender waits for this acknowledgment before sending the next part.

-> A is correct.

The data link layer adds physical source and destination addresses and an Frame Check Sequence (FCS) to the packet (on Layer 3), not segment (on Layer 4) -> B is not correct.

Packets are created when network layer encapsulates a segment (not frame) with source and destination host addresses and protocol-related control information. Notice that the network layer encapsulates messages received from higher layers by placing them into datagrams (also called packets) with a network layer header -> C is not correct.

The Network layer (Layer 3) has two key responsibilities. First, this layer controls the logical addressing of devices. Second, the network layer determines the best path to a particular destination network, and routes the data appropriately.

-> D is correct.

The Physical layer (not presentation layer) translates bits into voltages for transmission across the physical link -> E is not correct.

Question 2

Which layer of the OSI reference model uses the hardware address of a device to ensure message delivery to the proper host on a LAN?

A. physical
B. data link
C. network
D. transport

Answer: B

Explanation

The hardware address of a device or the Media Access Control (MAC) address is added in the Data Link layer. An Ethernet MAC address is a 48-bit binary value expressed as 12 hexadecimal digits (for example: 00:15:A4:CB:03:CA).

Question 3

Which layer of the OSI reference model uses flow control, sequencing, and acknowledgments to ensure that reliable networking occurs?

A. data link
B. network
C. transport
D. presentation
E. physical

Answer: C

Question 4

Which layer in the OSI reference model is responsible for determining the availability of the receiving program and checking to see if enough resources exist for that communication?

A. transport
B. network
C. presentation
D. session
E. application

Answer: E

Question 5

Data transfer is slow between the source and destination. The quality of service requested by the transport layer in the OSI reference model is not being maintained. To fix this issue, at which layer should the troubleshooting process begin?

A. presentation
B. session
C. transport
D. network
E. physical

Answer: D

Question 6

Which protocols are found in the network layer of the OSI reference model and are responsible for path determination and traffic switching?

A. LAN
B. routing
C. WAN
D. network

Answer: B

Question 7

Refer to the exhibit. An administrator pings the default gateway at 10.10.10.1 and sees the output as shown. At which OSI layer is the problem?

C:\> ping 10.10.10.1 Pinging 10.10.10.1 with 32 bytes of data: Request timed out. Request timed out. Request timed out. Request timed out. Ping statistics for 10.10.10.1: Packets: sent – 4, Received = 0, Lost – 4 (100% loss)

A. data link layer
B. application layer
C. access layer
D. session layer
E. network layer

Answer: E

Explanation

The Network layer is responsible for network addressing and routing through the internetwork. So a ping fails, you may have an issue with the Network layer (although lower layers like Data Link & Physical may cause the problem).

Question 8

Which of the following are types of flow control? (Choose three)

A. buffering
B. cut-through
C. windowing
D. congestion avoidance
E. load balancing

Answer: A C D

Explanation

Three types of flow control are buffering, windowing & congestion avoidance:

+ Buffering: If a device receives packets too quickly for it to handle then it can store them in a memory section called a buffer and proceed them later.

+ Windowing: a window is the quantity of data segments that the transmitting device is allowed to send without receiving an acknowledgment for them. For example:

With the window size of 1, the sending device sends 1 segment and the receiving device must reply with 1 ACK before the sending device can send the next segment. This “waiting” takes some time.

By increasing the window size to 3, the sending device will send up to 3 segments before waiting an ACK -> helps reduce the waiting time.

+ Congestion avoidance: lower-priority traffic can be discarded when the network is overloaded -> minimize delays.

Question 9

A network administrator is verifying the configuration of a newly installed host by establishing an FTP connection to a remote server. What is the highest layer of the protocol stack that the network administrator is using for this operation?

A. application
B. presentation
C. session
D. transport
E. internet
F. data link

Answer: A

Explanation

FTP belongs to Application layer and it is also the highest layer of the OSI model.

Question 10

A receiving host computes the checksum on a frame and determines that the frame is damaged. The frame is then discarded. At which OSI layer did this happen?

A. session
B. network
C. physical
D. data link
E. transport

Answer: D

Explanation

When using the term “frame” we can easily recognize it belongs to the Data Link layer. In this layer, an Frame Check Sequence (FCS) field is added to the frame to verify that the frame data is received correctly.

Question 11

As a frame leaves a Layer 3 device, the Layer 2 encapsulation information is changed from what it was when it entered the device. For what two reasons can this happen? (Choose two)

A. The data is moving from 10BASE-TX to 100BASE-TX.
B. The WAN encapsulation type has changed.
C. The data format has changed from analog to digital.
D. The source and destination hosts are in the same subnet.
E. The source and destination MAC addresses have changed.

Answer: B E

Question 12

Acknowledgement, Sequencing, and Flow control are characteristics of which OSI layer?

A. Layer 2
B. Layer 3
C. Layer 4
D. Layer 5
E. Layer 6
F. Layer 7

Answer: C

Cisco IOS Questions – Part 3

Here you will find answers to Cisco IOS Questions – Part 3

Note: If you are not sure about the boot sequence of a router/switch, please read my Cisco Router Boot Sequence Tutorial.

Question 1

Refer to the exhibit. A router boots to the prompt shown in the exhibit. What does this signify, and how should the network administrator respond?

rommon 1>

A. This prompt signifies that the configuration file was not found in NVRAM. The network administrator should follow the prompts to enter a basic configuration.
B. The prompt signifies that the configuration file was not found in flash memory. The network administrator should use TFTP to transfer a configuration file to the router.
C. The prompt signifies that the IOS image in flash memory is invalid or corrupted. The network administrator should use TFTP to transfer an IOS image to the router.
D. The prompt signifies that the router could not authenticate the user. The network administrator should modify the IOS image and reboot the router.

Answer: C

Explanation

If a Cisco router boots in ROMmon mode, it means:

+ The value of the configuration register is set to XXX0 (the boot field – fourth bit – is 0)
+ The router is unable to locate a valid Cisco IOS software image (you can use the “dir flash:” command in ROMmon mode to look for the IOS in the Flash then try to boot that flash with the “boot flash:<IOS image>” command).

If the IOS image is invalid or corrupted, the fastest way to re-install a new Cisco IOS software image on the router is to copy a new one from TFTP (with “tftpdnld” command).

Question 2

What should be done prior to backing up an IOS image to a TFTP server? (Choose three)

A. Make sure that the server can be reached across the network.
B. Check that authentication for TFTP access to the server is set.
C. Assure that the network server has adequate space for the IOS image.
D. Verify file naming and path requirements.
E. Make sure that the server can store binary files.
F. Adjust the TCP window size to speed up the transfer.

Answer: A C D

Question 3

Which two privileged mode cisco ios commands can be used to determine a cisco router chassis serial number? (choose two)

A. show inventory
B. show flash filesys
C. dir flash:|include chassis
D. show diag
E. show controllers

Answer: A D

Question 4

Which command helps a network administrator to manage memory by displaying flash memory and NVRAM utilization?

A. show secure
B. show file systems
C. show flash
D. show version

Answer: B

Question 5

A network administrator changes the configuration register to 0×2142 and reboots the router. What are two results of making this change? (Choose two)

A. The IOS image will be ignored.
B. The router will prompt to enter initial configuration mode.
C. The router will boot to ROM.
D. Any configuration entries in NVRAM will be ignored.
E. The configuration in flash memory will be booted.

Answer: B D

Explanation

The router bypasses the startup configuration stored in NVRAM during its boot sequence so the router will enter initial configuration mode. This feature is normally used during a password recovery procedure.

Question 6

Refer to the exhibit. For what two reasons has the router loaded its IOS image from the location that is shown? (Choose two)

Router1> show version Cisco Internetwork Operating System Software IOS ™ 7200 Software (C7200-J-M), Experimental Version 11.3tl997091S:1647S2) [hampton-nitro-baseline 249] Copyright (c) 1986-1997 by cisco Systems, Inc. Compiled Wed 08-0ct-97 06:39 by hampton Image text-base: 0×60008900, data-base: 0x60B98000 ROM: System Bootstrap, Version 11.1(11855) [beta 2], INTERIM SOFTWARE BOOTPLASH: 7200 Software (C7200-BOOT-M), Version 11.1(472), RELEASE SOFTWARE (fcl) Router1 uptime is 23 hours, 33 minutes System restarted by abort at PC 0x6022322C at 10:50:SS PDT Tue Oct 21 1997 System image file is “tftp://112.16.1.129/hampton/nitro/c7200-j-mz” cisco 7206 (NPE150) processor with 57344K/8192K bytes of memory. <output omitted> Configuration register is 0×2102

A. Router1 has specific boot system command that instruct it to load IOS from TFTP server.
B. Router1 is acting as a TFTP server for other routers.
C. Router1 cannot locate a valid IOS image in flash memory.
D. Router1 defaulted to ROMMON mode and loaded the IOS image from a TFTP sewer.
E. Cisco routers will first attempt to load a image from TFTP for management purposes.

Answer: A C

Explanation

When powered on, the router first checks its hardware via Power-On Self Test (POST). Then it checks the configuration register to identify where to load the IOS image from. In the output above we learn that the Configuration register value is 0×2102 so the router will try to boot the system image from Flash memory first.

But we also see a line “System image file is “tftp://112.16.1.129/hampton/nitro/c7200-j-mz”. Please notice that this line tells us the image file that the device last started. In this case it is from a TFTP server. Therefore we can deduce that the router could not load the IOS image from the flash and the IOS image has been loaded from TFTP server.

Note:

If the startup-config file is missing or does not specify a location, it will check the following locations for the IOS image:

+ Flash (the default location)
+ TFTP server
+ ROM (used if no other source is found)

Cisco IOS – Part 2

Here you will find answers to Cisco IOS – Part 2

Note: If you are not sure about the boot sequence of a router/switch, please read my Cisco Router Boot Sequence Tutorial.

Question 1

When you are logged into a switch, which prompt indicates that you are in privileged mode?

A. %
B. @
C. >
D. $
E. #

Answer: E

Explanation

The “#” (like Switch#) indicates you are in privileged mode while the “>” indicates you are in user mode.

Note: The “#” sign in “Switch(config)#” indicates this is only accessible at privileged EXEC mode. The “(config)#” part indicates we are in configuration mode.

Below lists popular modes in Cisco switch/router:

Router>	User EXEC mode
Router#	Privileged EXEC mode
Router(config)#	Configuration mode
Router(config-if)#	Interface level (within configuration mode)
Router(config-router)#	Routing engine level (within configuration mode)
Router(config-line)#	Line level (vty, tty, async) within configuration mode

Question 2

Which command is used to copy the configuration from RAM into NVRAM?

A. copy running-config startup-config
B. copy startup-config: running-config:
C. copy running config startup config
D. copy startup config running config
E. write terminal

Answer: A

Explanation

The running-config is saved in RAM while the startup-config is saved in NVRAM. So in order to copy the configuration from RAM into NVRAM we use the command “copy running-config startup-config” (syntax: copy ).

Question 3

Which command is used to load a configuration from a TFTP server and merge the configuration into RAM?

A. copy running-config: TFTP:
B. copy TFTP: running-config
C. copy TFTP: startup-config
D. copy startup-config: TFTP:

Answer: B

Explanation

The syntax of the copy command is “copy ” so to copy a configuration from a TFTP server into RAM we use the command “copy TFTP: running-config”.

Question 4

There are no boot system commands in a router configuration in NVRAM. What is the fallback sequence that router will use to find an IOS during reload?

A. Flash, TFTP server, ROM
B. Flash, NVRAM, ROM
C. ROM, NVRAM, TFTP server
D. NVRAM, TFTP server, ROM
E. TFTP server, Flash, NVRAM

Answer: A

Explanation

When you turn the router on, it runs through the following boot process.

The Power-On Self Test (POST) checks the router’s hardware. When the POST completes successfully, the System OK LED indicator comes on.
The router checks the configuration register to identify where to load the IOS image from. A setting of 0×2102 means that the router will use information in the startup-config file to locate the IOS image. If the startup-config file is missing or does not specify a location, it will check the following locations for the IOS image:

1. Flash (the default location)
2. TFTP server
3. ROM (used if no other source is found)

The router loads the configuration file into RAM (which configures the router). The router can load a configuration file from:

+ NVRAM (startup-configuration file)
+ TFTP server
If a configuration file is not found, the router starts in setup mode.

Question 5

A Cisco router is booting and has just completed the POST process.It is now ready to find and load an IOS image. What function does the router perform next?

A. It checks the configuration register
B. It attempts to boot from a TFTP server
C. It loads the first image file in flash memory
D. It inspects the configuration file in NVRAM for boot instructions

Answer: A

Explanation

Same as Question 4

Question 6

Refer to the partial command output shown. Which two statements are correct regarding the router hardware? (Choose two)

system image file is “flash:c2600-do3s-mz.120-5.T1″ Cisco 2621 (MPC860) processor (revision 0×600) with 53248K/12288K bytes of memory Processor board ID JAD05280307 (3536592999) M860 processor: part number 0, mask 49 Bridging software. X.25 software, version 3.0.0. 2 FastEthernet/IEEE 802.3 interface(s) 2 Serial(sync/async) network interface(s) 2 Low-speed serial(sync/async) network interface(s) 16 terminal line(s) 32K bytes of non-volatile configuration memory. 16384K bytes of processor board system flash (Read/Write)

A. Total RAM size is 32 KB
B. Total RAM size is 16384 KB (16 MB)
C. Total RAM size is 65536 KB (64 MB)
D. Flash size is 32 KB
E. Flash size is 16384 KB (16 MB).
F. Flash size is 65536 KB (64 MB)

Answer: C E

Explanation

The line “Cisco 2621 (MPC860) processor (revision 0×600) with 53248K/12288K bytes of memory” tells how much RAM in your router. The first parameter (53248) specifies how much Dynamic RAM (DRAM) in your router while the second parameter (12288K) indicates how much DRAM is being used for Packet memory (used by incoming and outgoing packets) in your router. Therefore you have to add both numbers to find the amount of DRAM available on your router -> C is correct.

Note: Cisco 4000, 4500, 4700, and 7500 routers have separate DRAM and Packet memory, so you only need to look at the first number to find out the DRAM in that router.

The flash size is straightforward from the line “16384K bytes of processor board system flash (Read/Write)” -> E is correct.

(Reference: http://www.cisco.com/en/US/products/sw/iosswrel/ps1834/products_tech_note09186a00800fb9d9.shtml)

Question 7

Which router IOS commands can be used to troubleshoot LAN connectivity problems? (Choose three)

A. ping
B. tracert
C. ipconfig
D. show ip route
E. winipcfg
F. show interfaces

Answer: A D F

Explanation

The ping command can be used to test if the local device can reach a specific destination -> A is correct.

“tracert” is not a valid command in Cisco IOS commands, the correct command should be “traceroute” -> B is not correct.

The ipconfig command is not a valid command in Cisco IOS too -> C is not correct.

The “show ip route” command can be used to view the routing table of the router. It is a very useful command to find out many connectivity problems (like directly connected networks, learned network via routing protocols…) -> D is correct.

“winipcfg” is an old tool in Windows 95/98 to view IP settings of the installed network interfaces. But it is not a valid command in Cisco IOS commands -> E is not correct.

The “show interfaces” command is used to check all the interfaces on the local device only. It has very limited information to trouble LAN connectivity problem but it is the most reasonable to choose -> F is acceptable.

Question 8

Which two locations can be configured as a source for the IOS image in the boot system command? (Choose two)

A. RAM
B. NVRAM
C. flash memory
D. HTTP server
E. TFTP server
F. Telnet server

Answer: C E

Explanation

The following locations can be configured as a source for the IOS image:

1. + Flash (the default location)
2. + TFTP server
3. + ROM (used if no other source is found)
4. (Please read the explanation of Question 4 for more information)

Question 9

Refer to the exhibit. Why is flash memory erased prior to upgrading the IOS image from the TFTP server?

Router# copy tftp flash Address or name of remote host []? 192.168.2.167 Source filename []? c1600-k8sy-mz.123-16a.bin Destination filename [c1600-k8sy-mz.123-16a.bin]? Accessing tftp://192.168.2.167/ c1600-k8sy-mz.l23-16a.bin… Erasing flash before copying? [confirm] Erasing the flash filesystem will remove all files! continue? [confirm] Erasing device Eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee Eeeeeeeeeeeeeeeeeeeeeeeeeeeeeee …erased Erase of flash: complete Loading c1600-k8sy-mz.l23-16a.bin from 192.168.2.167 (via Ethernet0): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! [OK - 6888962/13777920 bytes] verifying checksum… OK (0x7BF3) 6888962 bytes copied in 209.920 secs (32961 bytes/sec) Router#

A. The router cannot verify that the Cisco IOS image currently in flash is valid
B. Flash memory on Cisco routers can contain only a single IOS image.
C. Erasing current flash content is requested during the copy dialog.
D. In order for the router to use the new image as the default, it must be the only IOS image in flash.

Answer: C

Explanation

During the copy process, the router asked “Erasing flash before copying? [confirm]” and the administrator confirmed (by pressing Enter) so the flash was deleted.

Note: In this case, the flash has enough space to copy a new IOS without deleting the current one. The current IOS is deleted just because the administrator wants to do so. If the flash does not have enough space you will see an error message like this:

%Error copying tftp://192.168.2.167/ c1600-k8sy-mz.l23-16a.bin (Not enough space on device)

Question 10

Which command reveals the last method used to powercycle a router?

A. show reload
B. show boot
C. show running-config
D. show version

Answer: D

Explanation

The “show version” command can be used to show the last method to powercycle (reset) a router