1. Which information is used by routers to forward a data packet toward its destination?
2. A computer has to send a packet to a destination host in the same LAN. How will the packet be sent?
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?
4. Which IPv4 address can a host use to ping the loopback interface?
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?
6. Which statement describes a feature of the IP protocol?
Explanation: IP protocol is a connection-less protocol, considered unreliable in terms of end-to-end delivery. It does not provide error control in the cases where receiving packets are out-of-order or in cases of missing packets. It relies on upper layer services, such as TCP, to resolve these issues. 7. Why is NAT not needed in IPv6?
8. Which parameter does the router use to choose the path to the destination when there are multiple routes available?
9. What are two services provided by the OSI network layer? (Choose two.)
Explanation: The OSI network layer provides several services to allow communication between devices:
Error detection, placing frames on the media, and collision detection are all functions of the data ink layer. 10. Within a production network, what is the purpose of configuring a switch with a default gateway address?
Explanation: A default gateway address allows a switch to forward packets that originate on the switch to remote networks. A default gateway address on a switch does not provide Layer 3 routing for PCs that are connected on that switch. A switch can still be accessible from Telnet as long as the source of the Telnet connection is on the local network. 11. What is a basic characteristic of the IP protocol?
Explanation: Internet Protocol (IP) is a network layer protocol that does not require initial exchange of control information to establish an end-to-end connection before packets are forwarded. Thus, IP is connectionless and does not provide reliable end-to-end delivery by itself. IP is media independent. User data segmentation is a service provided at the transport layer. 12. Which field in the IPv4 header is used to prevent a packet from traversing a network endlessly?
Explanation: The value of the Time-to-Live (TTL) field in the IPv4 header is used to limit the lifetime of a packet. The sending host sets the initial TTL value; which is decreased by one each time the packet is processed by a router. If the TTL field decrements to zero, the router discards the packet and sends an Internet Control Message Protocol (ICMP) Time Exceeded message to the source IP address. The Differentiated Services (DS) field is used to determine the priority of each packet. Sequence Number and Acknowledgment Number are two fields in the TCP header. 13. What is one advantage that the IPv6 simplified header offers over IPv4?
Explanation: The IPv6 simplified header offers several advantages over IPv4:
14. What IPv4 header field identifies the upper layer protocol carried in the packet?
Explanation: It is the Protocol field in the IP header that identifies the upper-layer protocol the packet is carrying. The Version field identifies the IP version. The Differential Services field is used for setting packet priority. The Identification field is used to reorder fragmented packets. 15. Refer to the exhibit. Match the packets with their destination IP address to the exiting interfaces on the router. (Not all targets are used.)
Explanation: Packets with a destination of 172.17.6.15 are forwarded through Fa0/0. Packets with a destination of 172.17.10.5 are forwarded through Fa1/1. Packets with a destination of 172.17.12.10 are forwarded through Fa1/0. Packets with a destination of 172.17.14.8 are forwarded through Fa0/1. Because network 172.17.8.0 has no entry in the routing table, it will take the gateway of last resort, which means that packets with a destination of 172.17.8.20 are forwarded through Serial0/0/0. Because a gateway of last resort exists, no packets will be dropped. 16. What information does the loopback test provide?
17. What routing table entry has a next hop address associated with a destination network?
18. How do hosts ensure that their packets are directed to the correct network destination?
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?
Explanation: The Flow Label in IPv6 header is a 20-bit field that provides a special service for real-time applications. This field can be used to inform routers and switches to maintain the same path for the packet flow so that packets will not be reordered. 20. What statement describes the function of the Address Resolution Protocol?
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.)
Explanation: A switch will flood a frame out of every port, except the one that the frame was received from, under two circumstances. Either the frame has the broadcast address as the destination address, or the destination address is unknown to the switch. 22. Which statement describes the treatment of ARP requests on the local link?
Explanation: One of the negative issues with ARP requests is that they are sent as a broadcast. This means all devices on the local link must receive and process the request. 23. Which destination address is used in an ARP request frame?
Explanation: The purpose of an ARP request is to find the MAC address of the destination host on an Ethernet LAN. The ARP process sends a Layer 2 broadcast to all devices on the Ethernet LAN. The frame contains the IP address of the destination and the broadcast MAC address, FFFF.FFFF.FFFF. The host with the IP address that matches the IP address in the ARP request will reply with a unicast frame that includes the MAC address of the host. Thus the original sending host will obtain the destination IP and MAC address pair to continue the encapsulation process for data transmission. 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?
Explanation: Issuing the arp –d * command on a PC will clear the ARP cache content. This is helpful when a network technician wants to ensure the cache is populated with updated information. 25. Refer to the exhibit. The exhibit shows a small switched network and the contents of the MAC address table of the switch. PC1 has sent a frame addressed to PC3. What will the switch do with the frame?
Explanation: The MAC address of PC3 is not present in the MAC table of the switch. Because the switch does not know where to send the frame that is addressed to PC3, it will forward the frame to all the switch ports, except for port 4, which is the incoming port. 26. Which two types of IPv6 messages are used in place of ARP for address resolution?
Explanation: IPv6 does not use ARP. Instead, ICMPv6 neighbor discovery is used by sending neighbor solicitation and neighbor advertisement messages. 27. What is the aim of an ARP spoofing attack?
28. Refer to the exhibit. PC1 attempts to connect to File_server1 and sends an ARP request to obtain a destination MAC address. Which MAC address will PC1 receive in the ARP reply?
29. Where are IPv4 address to Layer 2 Ethernet address mappings maintained on a host computer?
30. What important information is examined in the Ethernet frame header by a Layer 2 device in order to forward the data onward?
Explanation: The Layer 2 device, such as a switch, uses the destination MAC address to determine which path (interface or port) should be used to send the data onward to the destination device. 31. Match the commands to the correct actions. (Not all options are used.)
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?
Explanation: While at the privileged mode prompt such as Router#, type exit,press Enter, and the banner message appears. Power cycling a network device that has had the banner motd command issued will also display the banner message, but this is not a quick way to test the configuration. 33. A network administrator requires access to manage routers and switches locally and remotely. Match the description to the access method. (Not all options are used.)
Explanation: Both the console and AUX ports can be used to directly connect to a Cisco network device for management purposes. However, it is more common to use the console port. The AUX port is more often used for remote access via a dial up connection. SSH and Telnet are both remote access methods that depend on an active network connection. SSH uses a stronger password authentication than Telnet uses and also uses encryption on transmitted data. 34. Match the phases to the functions during the boot up process of a Cisco router. (Not all options are used.)
Explanation: There are three major phases to the bootup process of a Cisco router:
If a startup configuration file cannot be located, the router will enter setup mode by displaying the setup mode prompt. 35. Match the command with the device mode at which the command is entered. (Not all options are used.)
Explanation: The enable command is entered in R1> mode. The login command is entered in R1(config-line)# mode. The copy running-config startup-config command is entered in R1# mode. The ip address 192.168.4.4 255.255.255.0 command is entered in R1(config-if)# mode. The service password-encryption command is entered in global configuration mode. 36. What are two functions of NVRAM? (Choose two.)
Explanation: NVRAM is permanent memory storage, so the startup configuration file is preserved even if the router loses power. 37. A router boots and enters setup mode. What is the reason for this?
38. The global configuration command ip default-gateway 172.16.100.1 is applied to a switch. What is the effect of this command?
Explanation: A default gateway address is typically configured on all devices to allow them to communicate beyond just their local network.In a switch this is achieved using the command ip default-gateway <ip address>. 39. What happens when the transport input ssh command is entered on the switch vty lines?
Explanation: The transport input ssh command when entered on the switch vty (virtual terminal lines) will encrypt all inbound controlled telnet connections. 40. Refer to the exhibit. A user PC has successfully transmitted packets to www.cisco.com. Which IP address does the user PC target in order to forward its data off the local network?
41. Match the configuration mode with the command that is available in that mode. (Not all options are used.)
Explanation: The enable command is entered at the R1> prompt. The login command is entered at the R1(config-line)# prompt. The copy running-config startup-config command is entered at the R1# prompt. The interface fastethernet 0/0 command is entered at the R1(config)# prompt. 42. Which three commands are used to set up secure access to a router through a connection to the console interface? (Choose three.)
Explanation: The three commands needed to password protect the console port are as follows:
The interface fastethernet 0/0 command is commonly used to access the configuration mode used to apply specific parameters such as the IP address to the Fa0/0 port. The line vty 0 4 command is used to access the configuration mode for Telnet. The0and 4 parameters specify ports 0 through 4, or a maximum of five simultaneous Telnet connections. The enable secret command is used to apply a password used on the router to access the privileged mode. 43. Refer to the exhibit. Consider the IP address configuration shown from PC1. What is a description of the default gateway address?
44. Which two functions are primary functions of a router? (Choose two.)
Explanation: A router accepts a packet and accesses its routing table to determine the appropriate exit interface based on the destination address. The router then forwards the packet out of that interface. 45. What is the effect of using the Router# copy running-config startup-config command on a router?
Explanation: The command copy running-config startup-config copies the running-configuration file from RAM into NVRAM and saves it as the startup-configuration file. Since NVRAM is none-volatile memory it will be able to retain the configuration details when the router is powered off. 46. What will happen if the default gateway address is incorrectly configured on a host?
Explanation: When a host needs to send a message to another host located on the same network, it can forward the message directly. However, when a host needs to send a message to a remote network, it must use the router, also known as the default gateway. This is because the data link frame address of the remote destination host cannot be used directly. Instead, the IP packet has to be sent to the router (default gateway) and the router will forward the packet toward its destination. Therefore, if the default gateway is incorrectly configured, the host can communicate with other hosts on the same network, but not with hosts on remote networks. 47. What are two potential network problems that can result from ARP operation? (Choose two.)
Explanation: Large numbers of ARP broadcast messages could cause momentary data communications delays. Network attackers could manipulate MAC address and IP address mappings in ARP messages with the intent to intercept network traffic. ARP requests and replies cause entries to be made into the ARP table, not the MAC address table. ARP table overflows are very unlikely. Manually configuring static ARP associations is a way to prevent, not facilitate, ARP poisoning and MAC address spoofing. Multiple ARP replies resulting in the switch MAC address table containing entries that match the MAC addresses of connected nodes and are associated with the relevant switch port are required for normal switch frame forwarding operations. It is not an ARP caused network problem. 48. Open the PT activity. Perform the tasks in the activity instructions and then answer the question. Which interfaces in each router are active and operational?
R1: G0/0 and S0/0/0
R1: G0/1 and S0/0/1
R1: G0/0 and S0/0/0
R1: G0/0 and S0/0/1 Explanation: The command to use for this activity is show ip interface brief in each router. The active and operational interfaces are represented by the value “up” in the “Status” and “Protocol” columns. The interfaces in R1 with these characteristics are G0/0 and S0/0/0. In R2 they are G0/1 and S0/0/0. 49. Which term describes a field in the IPv4 packet header used to identify the next level protocol?
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?
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?
52. Which term describes a field in the IPv4 packet header used to detect corruption in the IPv4 header?
Refer to the exhibit. A network administrator is connecting a new host to the Payroll LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
54. Which term describes a field in the IPv4 packet header that contains a unicast, multicast, or broadcast address?
55. Which term describes a field in the IPv4 packet header used to limit the lifetime of a packet?
56. Which term describes a field in the IPv4 packet header that contains a 4-bit binary value set to 0100?
57. Which term describes a field in the IPv4 packet header used to identify the next level protocol?
58. Which term describes a field in the IPv4 packet header that contains a 4-bit binary value set to 0100?
59. What property of ARP causes cached IP-to-MAC mappings to remain in memory longer?
60. What property of ARP allows MAC addresses of frequently used servers to be fixed in the ARP table?
61. What property of ARP allows MAC addresses of frequently used servers to be fixed in the ARP table?
62. What property of ARP allows hosts on a LAN to send traffic to remote networks?
Refer to the exhibit. A network administrator is connecting a new host to the Registrar LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
64. What property of ARP forces all Ethernet NICs to process an ARP request?
65. What property of ARP causes a reply only to the source sending an ARP request?
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?
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?
68. What property of ARP causes the NICs receiving an ARP request to pass the data portion of the Ethernet frame to the ARP process?
Refer to the exhibit. A network administrator is connecting a new host to the Service LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
Refer to the exhibit. A network administrator is connecting a new host to the Medical LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
Refer to the exhibit. A network administrator is connecting a new host to the Registrar LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
Refer to the exhibit. A network administrator is connecting a new host to the Manager LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
Refer to the exhibit. A network administrator is connecting a new host to the Store LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
Refer to the exhibit. A network administrator is connecting a new host to the Store LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
Refer to the exhibit. A network administrator is connecting a new host to the Service LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
Refer to the exhibit. A network administrator is connecting a new host to the Medical LAN. The host needs to communicate with remote networks. What IP address would be configured as the default gateway on the new host?
|