12.6.4 Module Quiz - Network Troubleshooting (Answers)

12.6.4 Module Quiz – Network Troubleshooting Answers

1. Which statement describes the physical topology for a LAN?

It depicts the addressing scheme that is employed in the LAN.
It describes whether the LAN is a broadcast or token-passing network.
It defines how hosts and network devices connect to the LAN.
It shows the order in which hosts access the network.

Explanation: A physical topology defines the way in which computers and other network devices are connected to a network.

2. A network engineer is troubleshooting a network problem where users cannot access the FTP server at the same IP address where a website can be successfully accessed. Which troubleshooting method would be the best to apply in this case?

comparing IP settings on user workstations
top-down
bottom-up
divide-and-conquer

Explanation: The fact that some application layer services provided by a network device are operating successfully but others are not means that the lower OSI or TCP/IP layers are functional with the problem likely to be in the application layer.

3. A computer technician performed a number of actions to correct a problem. Some actions did not solve the problem, but eventually a solution was found. What should be documented?

everything that was done to try to solve the problem
only the solution, because this solved the problem
a description of the problem and solution
only the failed attempts, so that future technicians will know what not to try

Explanation: Everything that was done to solve a problem should be documented, including failed attempts and the eventual solution. A description of the problem would have been previously documented.

4. A network engineer is troubleshooting a network problem and can successfully ping between two devices. However, Telnet between the same two devices does not work. Which OSI layers should the administrator investigate next?

all of the layers
from the network layer to the application layer
from the network layer to the physical layer
only the network layer

Explanation: A successful ping indicates that everything is working on the physical, data link, and network layer. All of the other layers should be investigated.

5. While designing changes to a data center because of a new IoE implementation, a network administrator has the job of diagramming the new physical topology of the area. What should be included in the physical topology diagram?

technical specifications of firewalls
the service level agreement from the ISP
cable locations and lengths between servers and switches
the IP addressing scheme for all workstations in the company

Explanation: A physical topology diagram should document the locations of physical devices and their connections.

6. A network technician is troubleshooting an email connection problem. Which question to the end-user will provide clear information to better define the problem?

What kind of equipment are you using to send emails?
How big are the emails you tried to send?
Is your email working now?
When did you first notice your email problem?

Explanation: To efficiently establish exactly when the user first experienced email problems, an open-ended question should be asked so that the user can state the day and time that the problem was first noticed. Closed questions only require a yes or no answer which will require further questions to determine the actual time of the problem.

7. Which troubleshooting tool can be used to pinpoint the distance to a break in a network cable?

network analyzer
network analysis module
cable tester
digital multimeter

Explanation: Cable testers that include time-domain reflectometers (TDRs) can be used to find the location of breaks in cables by sending signals along the cable and waiting for them to be reflected back.

8. Which troubleshooting software is an example of a network management system tool?

LANsurveyor
CyberGauge
WhatsUp Gold
Wireshark

Explanation: WhatsUp Gold is a network management system tool. Both LANsurveyor and CyberGauge are baselining tool. Wireshark is a protocol analyzer.

9. What is the purpose of establishing a network baseline?

to document and analyze the network traffic
to help monitor and troubleshoot network performance
to provide an inventory of network devices
to verify the configuration of routers and switches on the network

Explanation: Establishing a network baseline is a tool for monitoring and troubleshooting network performance. A network baseline is a record of normal network performance over time. The performance information (or snapshot) is taken at regular and pre-determined intervals. During monitoring and troubleshooting, the current performance can be compared with the baseline in order to identify the anomalies.

10. After which step in the network troubleshooting process would one of the layered troubleshooting methods be used?

determining ownership
narrowing the scope
documenting symptoms
gathering symptoms from suspect devices

Explanation: A layered troubleshooting approach (top-down, bottom-up, or divide-and-conquer) is used to gather hardware and software symptoms from the suspect devices.

11. A company is setting up a website with SSL technology to protect the authentication credentials required to access the website. A network engineer needs to verify that the setup is correct and that the authentication is indeed encrypted. Which tool should be used?

fault-management tool
baselining tool
protocol analyzer
cable analyzer

Explanation: To verify that the authentication is indeed encrypted, the authentication process needs to be captured and investigated, which can be accomplished through a protocol analyzer, such as Wireshark. A baselining tool is used for automating the network documentation and baselining process. A fault-management tool is used to manage the fault tolerance of network devices . A cable analyzer is used to test and certify copper and fiber cables for different services and standards.

12. When should a network performance baseline be measured?

immediately after the main network devices restarted
during normal work hours of an organization
after normal work hours to reduce possible interruptions
when a denial of service attack to the network is detected and blocked

Explanation: The purpose of a network performance baseline is to record the characteristics of a network during normal operations. This can be used as a standard to determine when a network is performing abnormally. Measurements that are performed during particular circumstances (such as main network device restart or after working hours) will result in an inaccurate set of characteristics for the purpose of a baseline. A DoS attack might cause abnormal network performance, but once it is blocked, network performance should return to normal, so there is no immediate need to measure performance in order to establish a baseline.

13. A networked PC is having trouble accessing the Internet, but can print to a local printer and ping other computers in the area. Other computers on the same network are not having any issues. What is the problem?

The default gateway router does not have a default route.
The switch port to which the PC connects has an incorrect VLAN configured.
The PC has a missing or incorrect default gateway.
The link between the switch to which the PC connects and the default gateway router is down.

Explanation: Since other computers on the same network work properly, the default gateway router has a default route and the link between the workgroup switch and the router works. An incorrectly configured switch port VLAN would not cause these symptoms.

14. A technician installed a network adapter in a computer and wants to test network connectivity. The ping command can receive responses from workstations on the same subnet but not from remote workstations. What could be causing the problem?

The operating system is not compatible with the remote sites.
The TCP/IP protocol stack is not loaded.
The default gateway is incorrect.
The NIC driver is out of date.

Explanation: The default gateway is the interface IP address of the router that is connected to the local network. The function of the router is to enable communication among different networks. If the default gateway is not set or is incorrect, packets that are destined to other networks will not be able to reach the router, and hence there will be no communication to hosts that are located in other networks.

15. What network troubleshooting capability is provided by a cable analyzer?

testing and certifying of copper and fiber cables
generating reports on traffic that is consuming critical network resources
measuring electrical values of voltage, current, and resistance
discovering VLAN configuration and viewing switch interface details

Explanation: Cable analyzers are multifunctional handheld devices that are used to test and certify copper and fiber cables for different services and standards.

16. In which step of gathering symptoms does a network engineer determine whether the problem is at the core, distribution, or access layer of the network?

Determine ownership.
Determine the symptoms.
Document the symptoms.
Gather information.
Narrow the scope.

Explanation: In the “narrow the scope” step of gathering symptoms, a network engineer determines whether the network problem is at the core, distribution, or access layer of the network. After this step is complete and the layer is identified, the network engineer can determine which pieces of equipment are the most likely causes.

17. A team of engineers has identified a solution to a significant network problem. The proposed solution is likely to affect critical network infrastructure components. What should the team follow while implementing the solution to avoid interfering with other processes and infrastructure?

Change-control procedures
Knowledge base guidelines
One of the layered troubleshooting approaches
Syslog messages and reports

Explanation: Change-control procedures should be established and applied for each stage to ensure a consistent approach to implementing the solutions and to enable changes to be rolled back if they cause other unforeseen problems.

18. Which troubleshooting method begins by examining cable connections and wiring issues?

Bottom-up troubleshooting
Divide-and-conquer troubleshooting
Substitution troubleshooting
Top-down troubleshooting

Explanation: In bottom-up troubleshooting, you start with the physical components of the network and move up through the layers of the OSI model until the cause of the problem is identified.

19. An administrator is troubleshooting an Internet connectivity problem on a router. The output of the show interfaces gigabitethernet 0/0 command reveals higher-than-normal framing errors on the interface that connects to the Internet. At what layer of the OSI model is the problem likely occurring?

Layer 1
Layer 2
Layer 3
Layer 4
Layer 7

Explanation: Framing errors are symptoms of problems at the data link layer (Layer 2) of the OSI model.

20. Users report that the new website http://www.company1.biz cannot be accessed. The help desk technician checks and verifies that the website can be accessed with http://www.company1.biz:90. Which layer in the TCP/IP model is involved in troubleshooting this issue?

Application
Internet
Network access
Transport

Explanation: The issue is that the new website is configured with TCP port 90 for HTTP, which is different from the normal TCP port 80. Therefore, this is a transport layer issue.

21. A user reports that after an OS patch of the networking subsystem has been applied to a workstation, the workstation performs very slowly when connecting to network resources. A network technician tests the link with a cable analyzer and notices that the workstation sends an excessive number of frames smaller than 64 bytes and also other meaningless frames. What is the possible cause of the problem?

Cabling faults
Corrupted application installation
Corrupted NIC driver
Ethernet signal attenuation

Explanation: The symptom of excessive runt packets and jabber is typically a Layer 1 issue, such as caused by a corrupted NIC driver, which could be the result of a software error during the NIC driver upgrade process. Cable faults would cause intermittent connections, but in this case, the network is not touched, and the cable analyzer has detected frame problems, not signal problems. Ethernet signal attenuation is caused by an extended or long cable, but in this case, the cable has not been changed. A NIC driver is part of the operating system; it is not an application.

22. Which three pieces of information are typically recorded in a logical topology diagram? (Choose three.)

Cable specifications
Device locations
Device models and manufacturers
IP addresses and prefix lengths
Routing protocols
Static routes

Explanation: Information recorded on a logical network diagram may include device identifiers, IP addresses and prefix lengths, interface identifiers, connection type, Frame Relay DLCI for virtual circuits (if applicable), site-to-site VPNs, routing protocols, static routes, data link protocols, and WAN technologies used.

23. Which number represents the most severe level of syslog logging?

Explanation: The lower the level number, the higher the severity level. By default, all messages from levels 0 to 7 are logged to the console.