Communicating Between Networks

4. Which IPv4 address can a host use to ping the loopback interface? 126.0.0.1 127.0.0.0 126.0.0.0 127.0.0.1

127.0.0.1

60. What property of ARP allows MAC addresses of frequently used servers to be fixed in the ARP table? A static IP-to-MAC address entry can be entered manually into an ARP table. Entries in an ARP table are time-stamped and are purged after the timeout expires. The type field 0x806 appears in the header of the Ethernet frame. The port-to-MAC address table on a switch has the same entries as the ARP table on the switch.

A static IP-to-MAC address entry can be entered manually into an ARP table

29. Where are IPv4 address to Layer 2 Ethernet address mappings maintained on a host computer? neighbor table ARP cache routing table MAC address table

ARP cache

20. What statement describes the function of the Address Resolution Protocol? ARP is used to discover the IP address of any host on a different network. ARP is used to discover the IP address of any host on the local network. ARP is used to discover the MAC address of any host on a different network. ARP is used to discover the MAC address of any host on the local network.

ARP is used to discover the MAC address of any host on the local network

7. Why is NAT not needed in IPv6?​ Because IPv6 has integrated security, there is no need to hide the IPv6 addresses of internal networks.​ Any host or user can get a public IPv6 network address because the number of available IPv6 addresses is extremely large.​ The problems that are induced by NAT applications are solved because the IPv6 header improves packet handling by intermediate routers.​ The end-to-end connectivity problems that are caused by NAT are solved because the number of routes increases with the number of nodes that are connected to the Internet.

Any host or user can get a public IPv6 address because the number of available IPv6 addresses is extremely large

39. What happens when the transport input ssh command is entered on the switch vty lines? The SSH client on the switch is enabled. Communication between the switch and remote users is encrypted. The switch requires a username/password combination for remote access. The switch requires remote connections via a proprietary client software.

Communication between the switch and remote users is encrypted

32. A new network administrator has been asked to enter a banner message on a Cisco device. What is the fastest way a network administrator could test whether the banner is properly configured? Reboot the device. Enter CTRL-Z at the privileged mode prompt. Exit global configuration mode. Power cycle the device. Exit privileged EXEC mode and press Enter.

Exit privileged EXEC mode and press Enter

6. Which statement describes a feature of the IP protocol? IP encapsulation is modified based on network media. IP relies on Layer 2 protocols for transmission error control. MAC addresses are used during the IP packet encapsulation. IP relies on upper layer services to handle situations of missing or out-of-order packets.

IP relies on upper layer services to handle situations of missing or out-of-order packets

14. What IPv4 header field identifies the upper layer protocol carried in the packet? Protocol Identification Version Differentiated Services

Protocol

5. A computer can access devices on the same network but cannot access devices on other networks. What is the probable cause of this problem? The cable is not connected properly to the NIC. The computer has an invalid IP address. The computer has an incorrect subnet mask. The computer has an invalid default gateway address.

The computer has an invalid default gateway address

12. Which field in the IPv4 header is used to prevent a packet from traversing a network endlessly? Time-to-Live Sequence Number Acknowledgment Number Differentiated Services

Time-to-live

11. What is a basic characteristic of the IP protocol? connectionless media dependent user data segmentation reliable end-to-end delivery

connectionless

3. A router receives a packet from the Gigabit 0/0 interface and determines that the packet needs to be forwarded out the Gigabit 0/1 interface. What will the router do next? route the packet out the Gigabit 0/1 interface create a new Layer 2 Ethernet frame to be sent to the destination look into the ARP cache to determine the destination IP address look into the routing table to determine if the destination network is in the routing table

create a new Layer 2 Ethernet frame to be sent to the destination

50. Which term describes a field in the IPv4 packet header that contains an 8-bit binary value used to determine the priority of each packet? differentiated services destination IPv4 address source IPv4 address protocol

differentiated services

13. What is one advantage that the IPv6 simplified header offers over IPv4? smaller-sized header little requirement for processing checksums smaller-sized source and destination IP addresses efficient packet handling

efficient packet handling

52. Which term describes a field in the IPv4 packet header used to detect corruption in the IPv4 header? header checksum source IPv4 address protocol TTL

header checksum

42. Which three commands are used to set up secure access to a router through a connection to the console interface? (Choose three.) interface fastethernet 0/0 line vty 0 4 line console 0 enable secret cisco login password cisco

line console 0 login password cisco

26. Which two types of IPv6 messages are used in place of ARP for address resolution? anycast broadcast echo reply echo request neighbor solicitation neighbor advertisement

neighbor solicitation neighbor advertisement

44. Which two functions are primary functions of a router? (Choose two.) packet forwarding microsegmentation domain name resolution path selection flow control

packet forwarding path selection

49. Which term describes a field in the IPv4 packet header used to identify the next level protocol? protocol destination IPv4 address source IPv4 address TTL

protocol

8. Which parameter does the router use to choose the path to the destination when there are multiple routes available? the lower metric value that is associated with the destination network the lower gateway IP address to get to the destination network the higher metric value that is associated with the destination network the higher gateway IP address to get to the destination network

the lower metric value that is associated with the destination network

27. What is the aim of an ARP spoofing attack? to flood the network with ARP reply broadcasts to fill switch MAC address tables with bogus addresses to associate IP addresses to the wrong MAC address to overwhelm network hosts with ARP requests

to associate IP addresses to the wrong MAC address

56. Which term describes a field in the IPv4 packet header that contains a 4-bit binary value set to 0100? version source IPv4 address protocol TTL

version

58. Which term describes a field in the IPv4 packet header that contains a 4-bit binary value set to 0100? version differentiated services header checksum TTL

version

23. Which destination address is used in an ARP request frame? 0.0.0.0 255.255.255.255 FFFF.FFFF.FFFF AAAA.AAAA.AAAA the physical address of the destination host

FFFF.FFFF.FFFF

19. When transporting data from real-time applications, such as streaming audio and video, which field in the IPv6 header can be used to inform the routers and switches to maintain the same path for the packets in the same conversation? Next Header Flow Label Traffic Class Differentiated Services

Flow Label

47. What are two potential network problems that can result from ARP operation? (Choose two.) Manually configuring static ARP associations could facilitate ARP poisoning or MAC address spoofing. On large networks with low bandwidth, multiple ARP broadcasts could cause data communication delays. Network attackers could manipulate MAC address and IP address mappings in ARP messages with the intent of intercepting network traffic. Large numbers of ARP request broadcasts could cause the host MAC address table to overflow and prevent the host from communicating on the network. Multiple ARP replies result in the switch MAC address table containing entries that match the MAC addresses of hosts that are connected to the relevant switch port.

On large networks with low bandwidth, multiple ARP broadcasts could cause data communication delays Network attackers could manipulate MAC address and IP address mappings in ARP messages with the intent of intercepting network traffic

55. Which term describes a field in the IPv4 packet header used to limit the lifetime of a packet? TTL source IPv4 address protocol header checksum

TTL

24. A network technician issues the arp -d * command on a PC after the router that is connected to the LAN is reconfigured. What is the result after this command is issued? The ARP cache is cleared. The current content of the ARP cache is displayed. The detailed information of the ARP cache is displayed. The ARP cache is synchronized with the router interface.

The ARP cache is cleared

16. What information does the loopback test provide? The TCP/IP stack on the device is working correctly. The device has end-to-end connectivity. DHCP is working correctly. The Ethernet cable is working correctly. The device has the correct IP address on the network.

The TCP/IP stack on the device is working correctly

37. A router boots and enters setup mode. What is the reason for this? The IOS image is corrupt. Cisco IOS is missing from flash memory. The configuration file is missing from NVRAM. The POST process has detected hardware failure.

The configuration file is missing from NVRAM

45. What is the effect of using the Router# copy running-config startup-config command on a router? The contents of ROM will change. The contents of RAM will change. The contents of NVRAM will change. The contents of flash will change.

The contents of NVRAM will change

10. Within a production network, what is the purpose of configuring a switch with a default gateway address? Hosts that are connected to the switch can use the switch default gateway address to forward packets to a remote destination. A switch must have a default gateway to be accessible by Telnet and SSH. The default gateway address is used to forward packets originating from the switch to remote networks. It provides a next-hop address for all traffic that flows through the switch.

The default gateway address is used to forward packets originating from the switch to remote networks

64. What property of ARP forces all Ethernet NICs to process an ARP request? The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame. The source MAC address appears in the header of the Ethernet frame. The type field 0x806 appears in the header of the Ethernet frame. ARP replies are broadcast on the network when a host receives an ARP request.

The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame

66. What property of ARP causes the request to be flooded out all ports of a switch except for the port receiving the ARP request? The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame. The type field 0x806 appears in the header of the Ethernet frame. Entries in an ARP table are time-stamped and are purged after the timeout expires. ARP replies are broadcast on the network when a host receives an ARP request.

The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame

21. Under which two circumstances will a switch flood a frame out of every port except the port that the frame was received on? (Choose two.) The frame has the broadcast address as the destination address. The destination address is unknown to the switch. The source address in the frame header is the broadcast address. The source address in the frame is a multicast address. The destination address in the frame is a known unicast address.

The frame has the broadcast address as the destination address The destination address is unknown to the switch

46. What will happen if the default gateway address is incorrectly configured on a host? The host cannot communicate with other hosts in the local network. The switch will not forward packets initiated by the host. The host will have to use ARP to determine the correct address of the default gateway. The host cannot communicate with hosts in other networks. A ping from the host to 127.0.0.1 would not be successful.

The host cannot communicate with hosts in other networks

2. A computer has to send a packet to a destination host in the same LAN. How will the packet be sent? The packet will be sent to the default gateway first, and then, depending on the response from the gateway, it may be sent to the destination host. The packet will be sent directly to the destination host. The packet will first be sent to the default gateway, and then from the default gateway it will be sent directly to the destination host. The packet will be sent only to the default gateway.

The packet will be sent directly to the destination host

65. What property of ARP causes a reply only to the source sending an ARP request? The source MAC address appears in the header of the Ethernet frame. The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame. The type field 0x806 appears in the header of the Ethernet frame. ARP replies are broadcast on the network when a host receives an ARP request.

The source MAC address appears in the header of the Ethernet frame

38. The global configuration command ip default-gateway 172.16.100.1 is applied to a switch. What is the effect of this command? The switch will have a management interface with the address 172.16.100.1. The switch can be remotely managed from a host on another network. The switch can communicate with other hosts on the 172.16.100.0 network. The switch is limited to sending and receiving frames to and from the gateway 172.16.100.1.

The switch can be remotely managed from a host on another network

67. What property of ARP causes the NICs receiving an ARP request to pass the data portion of the Ethernet frame to the ARP process? The type field 0x806 appears in the header of the Ethernet frame. The destination MAC address FF-FF-FF-FF-FF-FF appears in the header of the Ethernet frame. Entries in an ARP table are time-stamped and are purged after the timeout expires. ARP replies are broadcast on the network when a host receives an ARP request.

The type filed in 0x806 appears in the header of the Ethernet frame

22. Which statement describes the treatment of ARP requests on the local link? They must be forwarded by all routers on the local network. They are received and processed by every device on the local network. They are dropped by all switches on the local network. They are received and processed only by the target device.

They are received and processed by every device on the local network

18. How do hosts ensure that their packets are directed to the correct network destination? They have to keep their own local routing table that contains a route to the loopback interface, a local network route, and a remote default route.​ They always direct their packets to the default gateway, which will be responsible for the packet delivery. They search in their own local routing table for a route to the network destination address and pass this information to the default gateway. They send a query packet to the default gateway asking for the best route.

They have to keep their own local routing table that contains a route to the loopback interface, a local network route, and a remote default route

1. Which information is used by routers to forward a data packet towards its destination? source IP address destination IP address source data-link address destination data-link address

destination IP address

54. Which term describes a field in the IPv4 packet header that contains a unicast, multicast, or broadcast address? destination IPv4 address protocol TTL header checksum

destination IPv4 address

30. What important information is examined in the Ethernet frame header by a Layer 2 device in order to forward the data onward? source MAC address source IP address destination MAC address Ethernet type destination IP address

destination MAC address

59. What property of ARP causes cached IP-to-MAC mappings to remain in memory longer? Entries in an ARP table are time-stamped and are purged after the timeout expires. A static IP-to-MAC address entry can be entered manually into an ARP table. The type field 0x806 appears in the header of the Ethernet frame. The port-to-MAC address table on a switch has the same entries as the ARP table on the switch.

entries in an ARP table are time-stamped and are purged after the timeout expires

57. Which term describes a field in the IPv4 packet header used to identify the next level protocol? protocol version differentiated services header checksum

protocol

17. What routing table entry has a next hop address associated with a destination network? directly-connected routes local routes remote routes C and L source routes

remote routes

9. What are two services provided by the OSI network layer? (Choose two.) performing error detection routing packets toward the destination encapsulating PDUs from the transport layer placement of frames on the media collision detection

routing packets toward the destination encapsulating PDUs from the transport layer

51. Which term describes a field in the IPv4 packet header that contains a 32-bit binary value associated with an interface on the sending device? source IPv4 address destination IPv4 address protocol TTL

source IPv4 address