Chapter 14. Answer Key 1

1. A, B, C, D, F

2. A, C, D, F

3. A, B, C, F

4. C

5. A

6. A, D

7. A

8. D

9. C

10. A

11. A, B, C

12. D

13. D

14. A, C

15. B

16. D

17. B

18. D

19. D

20. B

21. B

22. D

23. C

24. C

25. D

26. B

27. E

28. A

29. B

30. A

31. C

32. A

33. C

34. B

35. C

36. D

37. C

38. D

39. B

40. A, C

41. C

42. B

43. D

44. D

45. B

46. D

47. E

48. D

49. A, B, D

50. C

51. C

52. C

53. D

54. A, C, D, E

55. C

56. D

57. A

58. B

59. A

60. C

A1:	Answers A, B, C, D, and F are all correct. When creating documentation, you should determine the scope, maintain the documentation, be consistent, know your objective, and keep the documents accessible. Answer E is incorrect. You should only collect data that is relevant to your objective ”you should not attempt to document all obtainable parameters. Answer G is also incorrect. Cisco does not recommend documenting only physical interfaces.
A2:	Answers A, C, D, and F are all correct. Management IP address, speed, duplex, and VLAN information is all expected for a Layer 2 switch network configuration table. Answers B and E are incorrect. IP Address and Interface Name are elements that you would expect to see in a network configuration table for a router ”not a switch. Answer G ”routing protocol ”is also appropriate for a router network configuration table.
A3:	Answers A, B, C, and F are all correct. The Device name and purpose, DNS server address, network applications, and IP address/subnet mask information are all perfectly appropriate for a network configuration table for an end system. Answer D and E are incorrect. VLAN and Interface Name are more appropriate for the network configuration table of a switch. Answer G is incorrect. Trunk mode is appropriate for a switch network configuration table as well.
A4:	Answer C is correct. ipconfig /all displays IP information for hosts running Windows NT/2000/XP. Answer A allows you to view the routing table on Windows-based system. Answer B allows you to trace a path that packets take in the network. Answer D allows you to view the arp table, and answer E allows you to test connectivity between two systems.
A5:	Answer A is correct. ifconfig “a displays IP information for Unix and Mac OS hosts. Answer B is incorrect. The traceroute command allows you to trace the path packets take through an internetwork. Answer C is incorrect. The route command displays routing table information. Answer D is incorrect. The arp command allows the viewing of Layer 2 to Layer 3 address information. Answer E is incorrect. Ping allows you to test connectivity, not view all IP information. Answer F is incorrect. Ipconfig allows you to view IP information, but on a Windows-based machine.
A6:	Answers A and D are correct. Switches function at Layers 1 and 2 of the OSI reference model. Multilayer switches have the ability to also function at higher layers . Answers B, C, E, F, and G are all incorrect. Only multilayer switches function at the higher layers of the OSI model. These layers include the Network, Transport, Session, Presentation, and Application layers.
A7:	Answer A is correct. You should gather symptoms and then attempt to isolate the problem. Answers B, C, and D are all incorrect. You do not start correcting the problem after gathering symptoms ”you first attempt to isolate the problem. You also cannot document your solution at this time. Finally, you do not reverse any changes that did not correct the problem ”this might be performed later in the process.
A8:	Answer D is correct. Following the determination that a problem is within your boundary of control, you should narrow the scope, then determine and document symptoms. Answers A, B, and C are all incorrect. You do not document the symptoms, nor document the solution until you have narrowed the scope of the problem.
A9:	Answer C is correct. A Bottom-Up troubleshooting approach starts with the physical layer and works up the OSI model. Traceroute and ping are often used initially in this approach to test the first few layers. Answer A is incorrect. The divide and conquer approach does not involve starting at the bottom of the OSI model ”using this approach, any layer of the model might be appropriate for a start. Answer B is incorrect. The top down approach is not used here ”since ping and traceroute commands test lower layers. Answer D is also incorrect. Finally, there is no such troubleshooting approach as the logical hierarchy.
A10:	Answer A is correct. When you apply the divide and conquer approach toward troubleshooting, you select a layer and test in both directions from the starting layer. Answer B is incorrect. The top down approach would have you starting at the upper layers and working your way down. Answer C is incorrect. The bottom up approach would have you starting from the first couple of layers and moving up. Finally, answer D is incorrect. There is no such troubleshooting approach as the logical hierarchy.
A11:	Answers A, B, and C are correct. You should always determine the scope of the problem, apply your experience, and analyze the symptoms when you are selecting a troubleshooting approach. Answer D is incorrect. Documenting the problem is not considered a valid guideline according to Cisco Systems approach.
A12:	Answer D is correct. Address resolution errors are common symptoms of Data Link layer problems. Answers A, B, and C are all incorrect. Framing, line coding, and synchronization errors are all possible and common symptoms of Physical layer problems.
A13:	Answer D is correct. An increased number of interface errors is a possible symptom of Physical layer problems. Answers A, B, and C are all common symptoms of Data Link layer problems.
A14:	Answer A and C are correct. Ping is available from both user and privileged modes on Cisco equipment. Answers B and D are incorrect. Ping is not available from global configuration mode, nor line configuration mode.
A15:	Answer B is correct. If a network problem is at the Data Link layer and not the Physical layer, then the show interface command will indicate that the interface is up, but the line protocol is down. Answer A is incorrect. A Physical layer problem would show a "down, down" indication. Answer C is incorrect. If the interface has been administratively disabled, the results of the command will state that. Answer D is incorrect. Finally, the CDP configuration has no bearing on the output of this command.
A16:	Answer D is correct. The show controllers command displays the current internal status information for the interface controller cards. This command is often used to learn information about the cable type used with serial interfaces. Answer A is incorrect. The show version command provides information about the hardware in use. Answer B is incorrect. The show ip interfaces provides information regarding the TCP/IP configuration on interfaces. Answer C is incorrect. The show ip interfaces brief command provides a summary of IP information for interfaces.
A17:	Answer B is correct. The show cdp neighbor detail command displays device type, IP address, and the Cisco IOS version of the neighboring device. Answer A is incorrect. The show cdp neighbors command is excellent ”yet it does not display Layer 3 address information. Answer C is incorrect. The show controllers command displays the current internal status information for the interface controller cards. This command is often used to learn information about the cable type used with serial interfaces. Answer D is incorrect. There is no such command as show cdp ip interface brief .
A18:	Answer D is correct. netstat “rn displays the routing table in numeric form without querying a Domain Name System (DNS) server. Answer A is incorrect. The ping command allows you to test connectivity between two systems. Answer B is incorrect. The arp command displays the Layer 2 to Layer 3 address resolution information. Answer C is incorrect. There is no such command as show ip arp on such an end system.
A19:	Answer D is correct. winipcfg displays IP information for hosts running Windows 9x and Me. Answers A and B are incorrect. Ipconfig does not function on an Me-based system, nor does ipconfig /all . Answer C is incorrect. Tracert does not provide extensive IP configuration information.
A20:	Answer B is correct. A status indication of 0x02 means the Frame Relay switch has the DLCI and everything is operational. Answer A, C, D, and E are all incorrect. Possible values for the status field are as follows : 0x00 ” Added/inactive 0x02 ” Added/active 0x04 ” Deleted 0x08 ” New/inactive 0x0a ” New/active
A21:	Answer B is correct. Late collisions are an indication that there may be a mismatch in the duplex configurations of the interfaces on a connection. Answers A, C, and D are incorrect. Neither a poorly seated cable, nor an encapsulation mismatch produce late collisions. If the interface is administratively downed, late collisions are not possible.
A22:	Answer D is correct. Testing connectivity at each hop of a path is an excellent troubleshooting guideline, but at the Network layer. Answer A, B, C, and E are all incorrect. Checking pin outs, verifying interface configurations, checking operational status, and checking for bad cables are all excellent Physical and Data Link layer guidelines.
A23:	Answer C is correct. The passive interface command disables the sending of routing update information from a particular interface. Answers A and B are incorrect. Enabling or disabling split horizon controls whether an interface sends update information out an interface from which it was received. Answer D is incorrect. The no ip route command is used to remove a static route.
A24:	Answer C is correct. The ipconfig command when used with the /release switch releases DHCP information for the client. Answer A, B, and D are incorrect. There is no release option in the Network Settings applet of Control Panel. The winipcfg utility is not available. Finally, nslookup cannot release DHCP information.
A25:	Answer D is correct. You use the debug ip routing command to watch for routing updates. Answer A is incorrect. There is no command show ip routing . Answer B is incorrect. Debug ip events is not a valid command. Answer C is incorrect. Debug ip packets is not a valid command. Finally, there is no debug routing command so answer E is incorrect.
A26:	Answer B is correct. Following the initial configuration changes, you should evaluate the results and document the results of the changes. You should then verify that the problem is solved . Answers A, C, D, and E are incorrect. All other options here are valid guidelines; however, they should not be performed after making the initial configuration change.
A27:	Answer E is correct. The show ip interface command provides a wealth of information about the interface, including Layer 3 address information and outgoing and inbound access lists applied. The command in answer A is not a valid command. Answer B is incorrect. The show ip route command displays the IP routing table on the device. Answer C is incorrect. The show access-lists command displays the content of all access-lists. Answer D is incorrect. The show logging command allows you to view the contents of the logging buffer. The command used in answer F also is not a valid command.
A28:	Answer A is correct. You should first establish whether IP connectivity exists between the source and the destination according to Cisco's guidelines. All of the other options listed here are valid guidelines except answer E. None of these options should be the first step in the troubleshooting process.
A29:	Answer B is correct. You may use the nslookup command in order to quickly display the identity of the name server being used. There is no such command as answer A. Answers C and D is incorrect. Winipcfg is not a command available on a Unix system, nor is ipconfig . Answer E is incorrect. ttcp is not a valid command. Answer F is incorrect. Ifconfig is a valid command on a Unix system, but it would not be as efficient as nslookup in this case.
A30:	Answer A is correct. You can use the telnet {ip address} 25 command in order to quickly verify and test SMTP protocol functionality. Answer B is incorrect. The port of 110 is inappropriate for testing SMTP. Answer C does not properly test SMTP, nor does the debug smtp events command (answer D), which is not a valid command. Answer E is incorrect. The ping command can be used to test connectivity, but it does not test SMTP specifically .
A31:	Answer C is correct. You use the ip access- group command in order to apply an IP access list to an interface. This is an interface configuration command. Answers A and B are not valid commands, nor are answers D and E.
A32:	Answer A is correct. A read-write community string helps to protect read/write access to Cisco devices using Cisco SNMP. The correct command to apply a read-write string to your router is snmp-server community rw {string} Answers B, C, D, and E are incorrect. All other commands presented here are invalid commands.
A33:	Answer C is correct. If you are calling TAC for assistance and the problem appears to be with only a few routers, you should capture the output from the show tech command on these routers. Answer A is incorrect. The copy flash tftp command allows you to back up your IOS. Answer B allows you to back up your backup configuration. Answer D allows you to see a summary of interface information. Finally, answer E allows you to obtain specific information about the hardware in use.
A34:	Answer B is correct. Use the snmp-server enable traps command to configure unsolicited network management alarms. Typically, you configure the router to send these alarms to a trap receiver, such as a CiscoWorks 2000 system. Answer A is incorrect. The ip http accounting command allows you to audit HTTP usage. Answer C is incorrect. The ip helper-address command allows you to forward broadcast messages. Answer D is incorrect. The service dhcp command allows the configuration of a DHCP server. Answer E is incorrect. The enable snmp traps command produces an error, as it is not a valid command.
A35:	Answer C is correct. Once you have made initial configuration changes and documented these changes, you should verify that the problem is solved and ensure that your solution did not introduce other problems. All of the answers listed here are valid guidelines except answer E. Only one of these guidelines should follow the step described, however.
A36:	Answer D is correct. You can rely on the show cdp neighbor command in order to complete the Device Discovery stage of the network documentation process. All of the other options listed here are valid stages except answer E. None of these would involve the show cdp neighbor command with the exception of the Device Discovery stage.
A37:	Answer C is correct. You should use the show isdn status command to display information about memory, Layer 2 and Layer 3 timers, and the status of ISDN channels. Answer A is incorrect. show isdn summary is not a valid command. Answer B is incorrect. The show isdn layers command is not valid. Answer D is not a valid command, nor is answer E.
A38:	Answer D is correct. You should use the show ip arp command to display the Address Resolution Protocol (ARP) cache. Answer A is incorrect. The show ip hosts command allows you to see the name to IP mappings created on the device. Answer B is incorrect. The show ip route command displays the routing table. Answer C is incorrect. The show ip interface command displays IP-specific information regarding interfaces. Answer E is not a valid command.
A39:	Answer B is correct. You should use the show frame-relay map command to display the current map entries and information about the connections. Answer A is incorrect. Show frame-relay is used with additional keywords. Answer C is not a valid command. Nor is answer D. Answer E is incorrect. The show arp command provides information about Ethernet ARP, not frame-relay.
A40:	Answer A and C are correct. In order to perform this test, you must use ping in Privileged mode. You initiate the test by typing the ping command and responding to the prompts. Both of these options mentioned are available without accessing the extended commands. Answer B is incorrect. Extended pings cannot be performed in user mode. Answer D is incorrect. You do not need the extended commands in order to configure the test described here. Answer E is incorrect. This ping test described is indeed possible.
A41:	Answer C is correct. A quick method of verifying DNS is to use IP addresses in place of host names when testing for connectivity. If tests pass with IP addresses and not with names , DNS is a potential problem. Answer A is incorrect. Routing table entries do not typically troubleshoot DNS issues. Answer B is incorrect. Examining the router configuration is also not a typical DNS troubleshooting step. Answer D is incorrect. There is no such thing as obsolete address resolution entries. Answer E is incorrect. Ping or trace can be used, but this is not the simplest testing method available. Answer F is also incorrect. Pinging the fully qualified domain name of the DNS server is not a help.
A42:	Answer B is correct. You use the debug ip packet EXEC command to display general IP debugging information and IP security option (IPSO) security transactions. Answer A is incorrect. There is no such command as show ip access . Answer C is incorrect. The show ip buffers command is not valid. Answer D is incorrect. debug ip traffic is not a valid command. Answer E is incorrect. Show ip transmitted is not a valid command. Answer F is incorrect. Show ip protocols is used to verify the dynamic routing protocols running on a router.
A43:	Answer D is correct. You can use the debug arp privileged EXEC command to display information on Address Resolution Protocol (ARP) transactions. Answers A, B, C, and E are incorrect. None of the other options in this question are completed through the use of the debug arp command.
A44:	Answer D is correct. Modern versions of the Cisco IOS cause the LMI type to be auto detected . While answers A, B, and C are all valid LMI types, the default configuration is auto-detection. Answer E is not an LMI type.
A45:	Answer B is correct. By default, logging of messages is sent to the console terminal. Answers A, C, D, and E are all incorrect. All other options here are not the default configuration.
A46:	Answer D is correct. Logging to the console is the default configuration on Cisco equipment. Logging to an internal buffer produces the least overhead, however. Answers A, B, C, and E are all incorrect. All other answers listed here produce more overhead than logging to the internal buffer.
A47:	Answer E is correct. You can use the show cdp neighbors detail command in order to view network protocol information about neighboring Cisco devices. Answers A, B, C, D, and F are invalid commands.
A48:	Answer D is correct. Clearing the counters will not produce an interface reset. Answers A, B, and C are incorrect because they all produce such behavior.
A49:	Answers A, B, and D are correct. You should be consistent with documentation. It should all use the same symbols, terminology, and styles. You should know the scope of your network documentation. You should also store the documentation where it is accessible on the job. Answers C and E are incorrect. You should maintain the documentation at all times, not just once per year. It is not recommended to include all Layer 2 information.
A50:	Answer C is correct. Topology diagram components that are related to end systems include physical location, access VLAN, ip address, subnet mask, device name, device purpose, operating system, version, network applications, and MAC address. Answers A, B, and D are incorrect. All other answers listed here include components that would be appropriate for switching topology diagrams.
A51:	Answer C is correct. The route print command allows you to view the routing table on an ip host. Answer A is incorrect. ipconfig allows you to view IP configuration information. Answer B is incorrect. tracert allows you to trace the path data takes as it moves through the network. Answer D is incorrect. Telnet allows you to log in to a remote system. Answer E is incorrect. Traceroute allows you to trace paths. Answer F is incorrect. Answers F and G are incorrect. show ip route and show route are not valid end system commands.
A52:	Answer C is correct. The data is at Layer 4, the Transport layer. Answers A, B, D, E, F, and G are all incorrect. The data exists at the Transport layer “ and can be at no other simultaneously .
A53:	Answer D is correct. The terminating phase involves removing the data control information and passing the data to an upper-layer application. Answers A, B, C, E, and F are incorrect. No other option involves converting the data as needed for the target application.
A54:	Answers A, C, D, E are all correct. All of the steps listed are valid with the exception of clear all logs. Answer B is incorrect. Clear all logs is not a valid step in the general troubleshooting process.
A55:	Answer C is correct. The Cisco IOS command set excels at allowing you to choose an intermediate level at which to begin troubleshooting. This is thanks to the many show and debug commands that are available in the Cisco IOS. Answer A and B are incorrect. The bottom-up and top-down approaches do not exploit the Cisco IOS command set like the divide and conquer approach does. Answer D is incorrect. There is no such approach as scatter.
A56:	Answer D is correct. There is no such functional area as Quality of Service management. Answers A, B, C, and E are incorrect. You can remember the five functional areas with the acronym FCAPS (Fault Management, Configuration Management, Accounting Management, Performance Management, and Security Management).
A57:	Answer A is correct. A cable tester is commonly used to check STP, UTP, 10BaseT, and coax for near-end crosstalk and noise. Answers B, C, D, and E are all incorrect. All other devices listed here server other purposes for network troubleshooting.
A58:	Answer B is correct. Connection-oriented protocols will request retransmission of data should the data prove to be missing or corrupt. Answer A is incorrect. There is no host-to-host protocol type in this course of study. Answer C is incorrect. Client/server is also not a valid protocol type for this discussion. Answer D is incorrect. Connectionless protocols are considered very fast, but they do not feature reliability, therefore there is not a request for retransmission of information. Answer E is incorrect. This is not a valid protocol type.
A59:	Answer A is correct. Connectionless protocols have the advantage of being fast. This is because they do not have to deal with the overhead incurred by connection-oriented protocols. Answers B, C, and D are incorrect. Connectionless protocols do not feature enhanced security or enhanced auditing, nor do they eliminate the need for upper-layer connections.
A60:	Answer C is correct. The embedded RMON agent allows monitoring of network traffic and does not require the use of a dedicated hardware probe of any kind. Answer A is incorrect. Cisco supports RMON1 and RMON2. Answer B is incorrect. RMON is disabled by default. Answer D is incorrect. RMON can monitor many types of segments, not just 10BaseT or 100BaseT.