CompTIA Network+ Chapter 5: Network Troubleshooting
Which of the following parameters enables you to specify the Time to Live (TTL) value of the messages that ping transmits?
-i
Which of the following parameters causes the ping tool to transmit messages continually until manually halted?
-t
Which of the following Windows commands enables you to delete the entire ARP cache?
arp -d ∗
Which of the following cable installation tools is likely to be the most expensive?
A cable certifier
Which of the following statements about cable certifiers are true? (Choose all that apply.)
A cable certifier eliminates the need for tools like tone generators and wiremap testers. Cable certifiers must be reconfigured whenever a new cable specification is standardized.
Which of the following tools can you use to create your own twisted pair patch cables? (Choose all that apply.)
A crimper is a device used for attaching connectors to patch cables. A wire stripper, while not essential to the process, can simplify the task of preparing the cable. A punchdown tool is used for attaching keystone connectors to cable ends, for use in wall plates and patch panels. A standard set of pliers is not used in the process of attaching connectors.
Ed is a first-tier support technician. He receives the help calls listed here. His job is to prioritize them based on their severity. Which of the following should be the problem that receives the lowest priority?
A fatal error that causes a single computer to fail
Which of the following is considered a systemwide error?
A fatal error that causes a single computer to fail
Ed is a first-tier support technician. He receives the help calls listed here. His job is to prioritize them based on their severity. Which of the following should be the problem that receives the highest priority?
A problem with a mission-critical backbone router that affects an entire network
Which of the following is a networkwide problem?
A problem with a router that connects an entire network to the Internet
Which of the following tools might you use when connecting internal twisted-pair cable runs to the keystone connectors that snap into wall plates? (Choose all that apply.)
A punchdown tool A wire stripper
You have a problem with a server or other network component that prevents many users from working. What type of problem is this?
A shared resource problem
Ralph is a new hire working on a network that uses Category 5 (Cat 5) Unshielded Twisted Pair (UTP) cable, which was installed several years ago. Over time, some of the paper labels that the original cable installers used to identify the wall plates and patch panel connectors have worn away or fallen off. As a result, Ralph has quite a few cable runs that he is unable to identify. After checking with his supervisor, Ralph discovers that the company has no cable testing equipment and is unwilling to hire a consultant just to identify cable runs. What is the most inexpensive tool Ralph can use to associate unlabeled wall plates with the correct patch panel ports?
A tone generator and locator
Alice is the network administrator of her company's network. The company has just moved into a building that has existing Category 6 (Cat 6) Unshielded Twisted Pair (UTP) cabling. However, none of the cable connections have been labeled, and Alice is trying to identify and document where each cable run starts and ends. Which tools can Alice use for this purpose? (Choose all that apply.)
Alice can use a tone generator and locator or a wiremap tester to identify and test cable connections.
Which of the following tools can you use to test the optical loss in a fiber-optic cable?
An optical loss test set (OLTS)
Ralph is a first-tier technician working the help desk. A user calls in, saying that when she turned her computer on that morning, nothing appeared on the screen. Which of the following should be Ralph's first question to the user?
Are the computer and monitor plugged in to AC power?
Ed has discovered that some of the twisted-pair cable runs on his newly installed Ethernet network are well over 100 meters long. Which of the following problems is his network likely to experience due to cable segments that are greater than the specified length?
Attenuation
Which of the following terms describes the progressive weakening of transmitted signals as they travel along a network medium?
Attenuation
Ralph is a first-tier technician working the help desk. After identifying a network problem submitted by multiple users, Ralph comes up with a theory specifying a possible source of the problem and sets about testing his theory. Unfortunately, testing indicates that Ralph's theory is wrong; the source he suspected is not the cause of the problem. Which of the following should not be the next step in Ralph's troubleshooting process?
Begin replacing components that might contribute to the problem
Ed is trying to troubleshoot a problem that has caused a wired network connection to slow down noticeably. Which of the following wired network problems will cause a drastic slowdown of a network connection, without causing it to fail completely? (Choose all that apply.)
Bottleneck Duplex mismatch
Which of the following devices is an essential tool for technicians working on telephone cables but is not needed for data networking cable installations?
Butt set
Which of the following devices is not one of the tools generally used by a data networking cable installer?
Butt set
Alice has been told by a consultant that the newly installed twisted-pair cable runs on her network might have split pairs. Which of the following cable testing tools can she use to detect split pairs?
Cable certifier
Which of the following troubleshooting tools can test cabling for length, attenuation, near-end crosstalk (NEXT), equal level far-end crosstalk (ELFEXT), propagation delay, delay skew, and return loss?
Cable certifier
Ralph is a new hire for a consulting firm that frequently performs cable installations. He is trying to learn more about the tools needed to install internal cable runs. To that end, which of the following statements about cable crimpers has Ralph found to be true?
Cable installers use a crimper to attach RJ45 connectors to lengths of bulk cable.
Alice is working the help desk when a user calls and reports that she is unable to connect to the Internet. Which of the following steps is the one Alice is least likely to perform first when troubleshooting the problem?
Check the configuration of the router connecting the LAN to the Internet
Which of the following should a troubleshooter look for when a duplex mismatch is suspected on an Ethernet network? (Choose all that apply.)
Collisions Runt frames CRC errors
Ralph is the network administrator of his company's network. He has had three users call the help desk to report that they are having problems connecting to the local application server. Comparing their stories, Ralph suspects that their Transmission Control Protocol (TCP) connections are being dropped. The users are not having problems connecting to any other hosts on the network. To troubleshoot this problem, Ralph decides to use a protocol analyzer. He wants to store and view only the traffic relating to the hosts and server that are having problems. How can Ralph do this?
Configure a capture filter
A user calls Alice at the help desk to report that her mouse has stopped working, she cannot access the Internet, and all of her email has disappeared from her inbox. Which of the following would be the best course of action for Alice to take?
Create a separate trouble ticket for each problem
Ralph has to spend the day completing a twisted-pair cable installation in his office. Contractors have already pulled the cables through the walls and ceilings. Ralph only has to attach connectors to the ends of the cables, both internal cable runs and patch cables. Which of the following tools will Ralph need? (Choose all that apply.)
Crimper Punchdown tool
Which step of the troubleshooting model involves identifying whether hardware or software has been recently installed or reconfigured?
Determine if anything has changed.
After experiencing some problems with devices connected to the company's fiber-optic network, Alice brings in a contractor to test the fiber-optic cable runs. The contractor detects a significant amount of decibel (dB) loss in some of the cable runs, which could be the source of the problems. Which of the following are possible causes of the decibel loss? (Choose all that apply.)
Dirty optical cables Excessive cable length
In the standard troubleshooting methodology, which of the following steps appears last, but must actually be practiced throughout the troubleshooting process?
Document findings, actions, and outcomes
In which troubleshooting step do you create a record of your activities and inform the user of what happened and why?
Document findings, actions, and outcomes
Which of the following are reasons for documenting a network problem or incident? (Choose all that apply.)
Documentation makes it easier to escalate calls to senior technicians. Documentation makes it easier to prioritize each help call.
Alice has recently installed some new computers onto her Gigabit Ethernet network. To ensure the best possible network performance, she has configured the network adapters in the new computers to run at 1 Gbps speed and use full-duplex communication. Once the computers are in service, however, Alice begins getting reports of extremely poor network performance on those machines. She tries running some ping tests and does not see any problem. She calls in a consultant to perform a packet analysis, and the consultant detects large numbers of packet collisions, late collisions, Cyclic Redundancy Check (CRC) errors, and runt frames. Which of the following could conceivably be the problem?
Duplex mismatch
When you troubleshoot a network problem, it is possible to introduce another problem while attempting to fix the original one. In which step of the troubleshooting process should you be aware of the residual effects that changes might have on the network?
Establish a plan of action to resolve the problem
When troubleshooting, you begin by taking steps to identify the problem. After you do this, which of the following steps should you perform next?
Establish a theory of probable cause
In which troubleshooting step do you try to duplicate a network problem to logically and methodically eliminate elements that are not the source of the problem?
Establish a theory of probable cause.
Which of the following statements about multitiered technical support organizations are true? (Choose all that apply.
Help calls are always escalated to second-tier technicians when they involve mission-critical network components such as routers. First-tier technicians generally handle desktop problems. First-tier technicians are generally less experienced than second-tier technicians.
Which of the following troubleshooting steps involves prioritizing trouble tickets based on the severity of the problem?
Identify symptoms of the problem
In which troubleshooting step is a trouble ticket created?
Identify the problem
Which of the following troubleshooting steps involves asking the user preliminary questions such as, "What were you doing when the problem occurred?"
Identify the problem
Delays in the transmission of data packets over a network can result in temporary service interruptions, dropouts, or even data loss. Which of the following terms is used to describe these delays?
Jitter
Which of the following indicators can you use to determine whether an adapter is connected to a functioning hub or switch?
Link pulse LED
Alice takes a call from a user who is unable to send email to a colleague in one of the company's branch offices. Alice begins by having the user try to send emails to different people at the branch office, to people in the local office, and to people on the Internet. She then checks the user's Internet Protocol (IP) configuration settings, the computer's Local Area Network (LAN) communication, and the cable connection to the network. Which of the following approaches is Alice using to troubleshoot the problem?
OSI top-to-bottom
Ralph is testing a twisted-pair cable run using a tone generator and locator. When he applies the tone generator to one particular wire at one end of the cable, he fails to detect a tone at the other end. Which of the following faults has Ralph discovered?
Open
Which of the following troubleshooting tools is not used to test copper cabling installations?
Optical Time Domain Reflectometer (OTDR)
Which of the following statements about prioritizing help calls are true? (Choose all that apply.)
Problems with shared resources take precedence over individual desktop problems. Networkwide problems take precedence over departmental problems.
What is the name of the tool shown in the following figure?
The device shown in the figure is a butt set, a basic tool of telephone installers and line workers. By connecting the clips to pins in a punchdown block, you can access telephone circuits in order to test them or place telephone calls.
Ralph wants to use Power over Ethernet (PoE) to supply power to security cameras located throughout his company's datacenter. The Ethernet network is currently running at Gigabit Ethernet speed, but Ralph is planning to downgrade the camera connections to 100Base-TX, because that standard has two wire pairs free for the transmission of power. Which of the following statements about Ralph's plan is true?
Ralph's plan will work, but it is not necessary to downgrade the connections to 100Base-TX.
A routine test of a newly installed twisted-pair cable run with a wiremap tester indicates that there is a short circuit on one of the wires. Which of the following procedures might possibly correct the fault?
Replace the connectors at both ends of the cable run
Which of the following types of cables is used to connect a terminal to the console port of a router or switch?
Rollover
A single Windows user suddenly cannot connect to any hosts on the network (local or remote). Alice interviews the user and finds out that he made some changes to his computer's Internet Protocol (IP) configuration properties. What should she do next?
Run the ipconfig command to view the local configuration
Ralph is testing a twisted-pair cable run using a tone generator and locator. When he applies the tone generator to a particular pin at one end of the cable, he detects a tone on two pins at the other end. Which of the following faults has Ralph discovered?
Short
After connecting a tone generator to the green wire at one end of a twisted-pair cable run, Ralph proceeds to the other end of the cable and touches the locator to each of the eight pins in turn. The green wire and the green striped wire both produce a tone. What type of wiring fault has Ralph discovered?
Short circuit
Ed is trying to troubleshoot a problem with his wired network, and his research has led him to a list of possible network faults. The list is rather old, however, and Ed is wondering if some of the problems are relevant. Which of the following wired network problems no longer occur with modern Gigabit Ethernet switches and network adapters in their default configurations? (Choose all that apply.)
Speed mismatch Duplex mismatch)
Ed is trying to troubleshoot a problem that has caused a wired network connection to fail completely. Which of the following wired network problems will cause a complete failure of a network connection? (Choose all that apply.)
Speed mismatch TX/RX reversal Bad switch port
Ralph is using a tone generator and locator to test some newly installed twisted-pair cable runs on his network. Which of the following cable faults will he be unable to detect?
Split pair
Which of the following cable faults increases a twisted-pair cable's susceptibility to crosstalk?
Split pair
Ed is experiencing poor network performance on some new twisted-pair cable runs. After ruling out all other causes, he tests the cables with a tone generator and locator and finds no faults. Finally, he examines the cable connectors more closely and finds that, while the pins at one end of the cable are correctly connected to their corresponding pins at the other end, in some cases there are two solid color wires twisted together in a pair. Which of the following types of faults has Ed discovered?
Split pairs
Which of the following types of Unshielded Twisted Pair (UTP) wiring faults cannot be detected by a wiremap tester?
Split pairs
Which of the following types of patch cables is used to connect a computer to a wall plate?
Straight through
Which of the following protocols does the ping program never use to carry its messages?
TCP
Which of the following application layer protocols includes a program that enables a user to log on to a network device and execute commands on the remote system using a command-line interface? (Choose all that apply.)
Telnet File Transfer Protocol (FTP)
Alice receives a call in which a user reports that he is unable to send print jobs to the network-attached workgroup printer near his desk. Which of the following tasks should Alice perform first?
Test network connectivity to the printer using the ping utility.
Which step of the troubleshooting model involves replacing components until a faulty hardware device is identified?
Test the theory to determine the cause
Ralph is attempting to access a Domain Name System (DNS) server located on the other side of a router, but his attempt fails with an error stating that the destination port UDP 53 is unreachable. His first step in troubleshooting the problem is to try using the nslookup utility to access that specific DNS server. This too fails. Next, he uses the ping utility with the DNS server's Internet Protocol (IP) address. The ping test is successful, indicating that the server is up and running. Which of the following are possible causes of the problem? (Choose all that apply.)
The DNS process on the remote server is not running. here is a firewall blocking the DNS server's UTP 53 port.
Which of the following commands enables you to view the Address Resolution Protocol (ARP) table stored in memory?
arp -a
What is the function of the tool shown in the following figure?
The device shown in the figure is a crimper, which is used to create patch cables by attaching connectors to both ends of a relatively short length of bulk cable. This tool is not capable of performing any of the tasks described in the other options.
What is the function of the tool shown in the following figure?
The device shown in the figure is a multimeter, which is used to measure the electric current on a copper conductor, such as an Unshielded Twisted Pair (UTP) network. This tool is not capable of performing any of the tasks described in the other options.
What is the function of the tool shown in the following figure?
The device shown in the figure is a punchdown tool, used to connect Unshielded Twisted Pair (UTP) cable ends to the keystone connectors used in modular wall plates and patch panels. After lining up the individual wires in the cable with the connector, one uses the tool to press each wire into its slot. The tool also cuts the wire sheath to make an electrical contact and trims the end of the wire. This tool is not capable of performing any of the tasks described in the other options.
What is the function of the tool shown in the following figure?
The device shown in the figure is a tone generator and locator, used to test Unshielded Twisted Pair (UTP) wiring and detect certain basic wiring faults. This tool is not capable of performing any of the tasks described in the other options.
Alice's company has moved to a building that was prewired for twisted-pair Ethernet. However, since installing the company's Gigabit Ethernet equipment using the existing cable runs, performance has been poor. After performing some packet captures and analyzing the traffic samples, Alice discovers that there are a great many Ethernet frames being retransmitted. Next, she examines the cable runs in the drop ceilings. They do not appear to be overly long, and they do not appear to run near any major sources of electromagnetic interference. Which of the following could be the problem?
The existing cable is not rated for use with Gigabit Ethernet.
Alice has a network with a Domain Name System (DNS) server, a proxy server, and an Internet router. A user is complaining that she suddenly cannot connect to hosts on her own Local Area Network (LAN) and other internal LANs, and she cannot access hosts on the Internet. What is the likeliest problem?
The user's local configuration
What is the name for a device that determines the length of a cable by transmitting a signal at one end and measuring how long it takes for a reflection of the signal to return from the other end?
Time-domain reflectometer
Ralph is testing some newly installed twisted-pair cable runs on his network using a wiremap tester, and he has found one run that appears to have a cable break. However, the connectors at both ends are correctly installed, so the break must be somewhere inside the cable itself, which is nearly 100 meters long. Which of the following tools can Ralph use to determine the location of the cable break? (Choose all that apply.)
Time-domain reflectometer Cable certifier
Ralph is working on a new twisted-pair network cable installation on which the individual cable runs were not properly labeled as they were pulled. Ralph now has to trace each of the cable ends in the office area to the correct cable end in the data center and label them correctly. Which of the following tools should Ralph use to locate the correct cable in a bundle of unlabeled cable ends?
Tone generator and locator
Ralph's company has expanded to include an additional building on the far end of the corporate campus, approximately 4 kilometers away from the building housing the datacenter. A single-mode fiber-optic cable connection has been installed between the new building and the datacenter for a 1000Base-BX10 connection, but the cable is not yet connected to a transceiver at the datacenter end. Noticing that there is a 1000Base-SX transceiver module in the datacenter storeroom, Ralph is wondering if he could use this on the new cable run. Which of the following are reasons why this might not work? (Choose all that apply.)
Transceiver mismatch Incorrect cable type Excessive cable length Wavelength mismatch
A user reports that she cannot connect to a server on her network. Ed wants to identify the scope of the problem, so he tries to reproduce the problem on the user's computer. The problem still remains. No other users are reporting this problem. What is the next logical step that Ed should perform to identify the affected area?
Try performing the same task on another computer attached to the same segment.
Users are having trouble connecting to Internet hosts. Alice suspects that there is a problem with the Domain Name System (DNS) server, and she wants to verify this. Which of the following steps can she take to determine whether the DNS server is resolving Internet hostnames?
Try to connect to a host using the IP address instead of the hostname
Which of the following are not general troubleshooting steps? (Choose all that apply.)
Verify that the client's Internet Protocol (IP) configuration is correct Verify that the router is forwarding.
On Monday morning, Alice arrives at work to find multiple email and telephone messages from users who are unable to access the Accounting department's file server. Which of the following are the best questions to ask during the beginning stage of the troubleshooting process? (Choose two.)
What has changed since the users were last able to access the server? Which users are reporting a problem, and where are they located?
Under which of the following conditions is a cable installer required to use plenum cable?
When cables are running through building air flow spaces
Which of the following Windows command-line utilities produced the output shown here? Interface: 192.168.2.24 --- 0x2 internet Address Physical Address Type 192.168.2.2 d4-ae-52-bf-c3-2d dynamic 192.168.2.20 00-26-c7-7e-00-e0 dynamic 192.168.2.22 00-90-a9-a2-43-8f dynamic 192.168.2.27 1c-c1-de-ca-1f-12 dynamic 192.168.2.28 30-f7-72-38-e9-1d dynamic 192.168.2.255 ff-ff-ff-ff-ff-ff static 224.0.0.22 01-00-5e-00-00-16 static 224.0.0.251 01-00-5e-00-00-fb static 224.0.0.252 01-00-5e-00-00-fc static 224.0.0.253 01-00-5e-00-00-fd static 239.255.255.250 01-00-5e-7f-ff-fa static 255.255.255.255 ff-ff-ff-ff-ff-ff static
arp
Ed has discovered that some of the twisted-pair cables on his newly installed network are running right alongside fluorescent light fixtures in the drop ceiling. Which of the following problems is the network likely to experience due to the cables' proximity to the fixtures?
electromagnetic interference (EMI)
Which of the following command-line utilities enables you to view the Internet Protocol (IP) configuration on a Unix or Linux host?
ifconfig
Which of the following Windows command-line utilities produced the output shown here? Active Connections Proto Local Address Foreign Address State TCP 127.0.0.1:5327 CM412:49770 ESTABLISHED TCP 127.0.0.1:49770 CM412:5327 ESTABLISHED TCP 127.0.0.1:52114 CM412:52115 ESTABLISHED TCP 192.168.2.24:2869 RT-M96U:42173 ESTABLISHED TCP 192.168.2.24:2869 RT-M96U:44356 ESTABLISHED TCP 192.168.2.24:51386 autodiscover:https ESTABLISHED TCP 192.168.2.24:51486 autodiscover:https ESTABLISHED TCP 192.168.2.24:51535 108-174-11-1:https ESTABLISHED TCP 192.168.2.24:51578 aki-cache:http TIME_WAIT TCP 192.168.2.24:51579 ia3s43-in-f142:http TIME_WAIT TCP 192.168.2.24:51591 208:https TIME_WAIT TCP 192.168.2.24:51592 208:https TIME_WAIT TCP 192.168.2.24:51593 198.8.20.
netstat
Which of the following commands displays the routing table on the local computer?
netstat -r
Ralph has been advised to check his Linux web servers for open ports that attackers might be able to use to penetrate the servers' security. Which of the following utilities can Ralph use to do this?
nmap
Which of the following command-line utilities enables you to generate Domain Name System (DNS) request messages?
nslookup
Which of the following utilities can you use to view resource record information on a particular Domain Name System (DNS) server? (Choose all that apply.)
nslookup and dig
Ralph's company has engaged a firm of wiring contractors to install some new fiber-optic cable runs. Before the cables are connected to any devices, Ralph wants to confirm that they have been installed to proper specifications. He brings in a contractor from another firm to test the cable runs. To test each cable run, the contractor connects a light source to one end of the cable and a measuring device to the other end. Which of the following is the correct name for this testing device?
optical loss test set (OLTS)
Which of the following command-line utilities is capable of performing the same basic function as traceroute or tracert?
pathping
Which of the following Windows command-line utilities produced the output shown here? Reply from 97.74.144.153: bytes=32 time=111ms TTL=53 Reply from 97.74.144.153: bytes=32 time=109ms TTL=53 Reply from 97.74.144.153: bytes=32 time=108ms TTL=53 Reply from 97.74.144.153: bytes=32 time=109ms TTL=53 Statistics for 97.74.144.153: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 108ms, Maximum = 111ms, Average = 109ms
ping
While performing a protocol analysis, Alice notes that there are many Internet Control Message Protocol (ICMP) packets in her captured traffic samples. She attributes these to her frequent use of Transmission Control Protocol/Internet Protocol (TCP/IP) troubleshooting tools. Which of the following utilities are used to test network layer characteristics of a host using ICMP messages? (Choose all that apply.)
ping tracert
Which of the following command lines will produce the output shown in the figure?
ping 10.0.0.1 -l 2048 -n 11
Which TCP/IP utility should you use to most easily identify a malfunctioning router on your network?
traceroute
Which of the following Windows command-line utilities produced the output shown here? 1 <1 ms <1 ms <1 ms RT-N86U [192.168.2.99] 2 3 ms 5 ms 4 ms 192.168.3.1 3 25 ms 30 ms 17 ms 10.172.1.1 4 20 ms 19 ms 29 ms gateway-BE1-EBlocal.eh.lpod.net [207.44.123.89] 5 26 ms 29 ms 29 ms gateway-be1-abn2abn2.ab.lpod.net [207.44.127.49] 6 * * * Request timed out. 7 111 ms 108 ms 109 ms be38.trmc0215-01.ars.mgmt.hox3.kkg [184.168.0.69] 8 108 ms 107 ms 108 ms be38.trmc0215-01.ars.mgmt.hox3.kkg [184.168.0.69] 9 106 ms 109 ms 108 ms ip-216-69-188-102.ip.srvr.net [216.69.188.102] 10 106 ms 108 ms 99 ms p3nlh153.shr.prod.phx3.srvr.net [97.74.144.153]
tracert
Which of the following Windows tools uses Internet Control Message Protocol (ICMP) messages and manipulates IPv4 time-to-live values to illustrate the route packets take through an internetwork?
tracert
