24. Network Troubleshooting Methodology

Question 1

1. Which of the following are not steps in the Network+ troubleshooting model? (Choose all that apply)
   a. Reboot the servers
   b. Identify the problem
   c. Test the theory to determine the cause
   d. Implement the solution or escalate as necessary
   e. Document findings, actions, outcomes, and lessons learned.
   f. Reboot all the routers

Answer 1

a, f. Rebooting servers and routers are not part of the troubleshooting model.

Question 2

2. You have a user who cannot connect to the network. What is the first thing you should check to determine the source of the problem?
   a. Workstation configuration
   b. Connectivity
   c. Patch cable
   d. Server configuration

Answer 2

b. You need to check the basic connectivity. The link light indicates that the network card is making a basic-level connection to the rest of the network. It is a very easy item to check, and if the link light is not lit, it is usually a very simple fix (like plugging in an unplugged cable).

Question 3

3. When wireless users complain that they are losing their connection to applications during a session, what is the source of the problem?
   a. Incorrect SSID
   b. Latency
   c. Incorrect encryption
   d. MAC address filter

Answer 3

b. When wireless users complain that the network is slow (latency) or that they are losing their connection to applications during a session, it is usually latency arising from a capacity issue.

Question 4

4. Several users can’t log in to the server. Which action would help you to narrow the problem down to the workstation, network or server?
   a. Run tracert from a workstation
   b. Check the server console for user connections.
   c. Run netstat on all workstations
   d. Check the network diagnostics

Answer 4

b. Although all of these are good tests for network connectivity, checking the server console for user connections will tell you whether other users are able to log into the server. If they can, the problem is most likely related to one of those users’ workstations. If they can’t, the problem is either the server or network connection. This helps narrow down the problem.

Question 5

5. A user can’t log into the network. She can’t even connect to the internet over the LAN. Other users in the same area aren’t experiencing any problems. You attempt to log in as this user from your workstation with her username and password and don’t experience any problems. However you cannot login with either her username or yours from her workstation. What is the likely cause of the problem?
   a. Insufficient rights to access the server.
   b. A bad patch cable
   c. Server down
   d. Wrong username and password

Answer 5

b. Because of all the tests given and their results, you can narrow the problem down to the network connectivity of that workstation. And because no other users in this user’s area are having the same problem, it can’t be the hub or server. You can log in as the user from your workstation, so you know it isn’t a rights issue or username/password issue. The only possible answer listed is a bad patch cable.

Question 6

6. A user is experiencing problems logging in to a Linux server. He can connect to the internet over the LAN. Other users in the same area aren’t experiencing any problems. You attempt logging in as this user from your workstation with his username and password and don’t experience any problems. However, you cannot log in with either his username or yours from his workstation. What is a likely cause of the problem?
   a. The Caps Lock key is pressed.
   b. The network hub is malfunctioning
   c. You have a downed server
   d. You have a jabbering NIC.

Answer 6

a. Because other users in the same area aren’t having a problem, it can’t be a downed server, network hub, or jabbering NIC. And because both you and the user can’t log in, more than likely it’s a problem specific to that workstation. The only one that would affect your ability to log in is the Caps Lock key being pressed. That will cause the password to be in all uppercase (which most server operating systems treat as a different password), and thus it will probably be rejected.

Question 7

7. You receive a call from a user who is having issues connecting to a new VPN. Which is the first step you should take?
   a. Find out what has changed
   b. Reboot the workstation
   c. Document the solution
   d. Identify the symptoms and potential causes

Answer 7

d. Since this is a new connection, you need to start by troubleshooting and identifying the symptoms and potential causes.

Question 8

8. A workstation presents an error message to a user. The message states that a duplicate IP address has been detected on the network. After establishing what has changed in the network, what should be the next step using the standard troubleshooting model?
   a. Test the result
   b. Select the most probable cause
   c. Create an action plan
   d. Identify the results and effects of the solution

Answer 8

b. According to the Network+ troubleshooting model, the next step would be step 2, establishing the most probable cause.

Question 9

9. You have gathered information on a network issue and determined the affected areas of the network. What is your next step in resolving this issue?
   a. You should implement the best solution for the issue
   b. You should test the best solution for the issue
   c. You should check to see if there have been any recent changes to this affected part of the network.
   d. You should consider any negative impact to the network that might be caused by a solution

Answer 9

c. After determining the affected area, you need to find out if any changes have taken place.

Question 10

10. A user calls you, reporting a problem logging in to the corporate intranet. You can access the website without problems using the user’s username and password . At your request, the user has tried logging in from other workstations but has been unsuccessful. What is the most likely cause of the error.
    a. The user is logging in incorrectly
    b. The network is down
    c. The intranet server is locked up
    d. The server is not routing packets correctly to that user’s workstation

Answer 10

a. Because the user can’t log in correctly from any machine, more than likely he is using the wrong procedure for logging in. Because no one else is having that problem (including yourself), the problem must be related to that user.

Question 11

11. You have just implemented a solution and you want to celebrate your success. But what should you do next before you start your celebrations?
    a. Gather more information about the issue
    b. Document the issue and the solution that was implemented
    c. Test the solution and identify other effects it may have
    d. Escalate the issue.

Answer 11

c. After you have implemented a solution, you need to test if the solution works and identify other effects it may have.

Question 12

12. You can ping the local router and web server that a local user is trying to reach, but you cannot reach the web page that resides on the server. From step 2 of the troubleshooting model, what is the possible problem that would lead to this situation?
    a. Your network cable is unplugged
    b. There is a problem with your browser
    c. Your NIC has failed
    d. Your web server is unplugged

Answer 12

b. Because you cannot reach the web page that resides on the server, the problem is most likely related to your browser.

Question 13

13. When troubleshooting an obscure network problem, what physical conditions should be reviewed to make sure the network device is operating correctly? (choose all that apply)
    a. Excessive heat
    b. Low/excessive humidity
    c. ESD problems
    d. None of the above

Answer 13

a, b, c. From a design standpoint, the physical environment for a server should be optimised for items such as placement, temperature and humidity. When troubleshooting, don’t forget to check the physical conditions under which the network device is operating. Check for problems such as those mentioned here as well as EMI/RFI problems, power problems, and unplugged cables

Question 14

14. Which of the following is not a basic physical issue that can occur on a network when a user is connected via cable?
    a. Crosstalk
    b. Shorts
    c. Open impedance mismatch
    d. DNS configurations

Answer 14

d. Because most of today’s networks still consist of large amounts of copper cable, networks can suffer from the physical issues that have plagued all networks since the very beginning of networking (and the answers here are not the complete list). Newer technologies and protocols have lessened these issues but have not resolved them completely.

Question 15

15. You are troubleshooting a LAN switch and have identified the symptoms. What is the next step you should take?
    a. Escalate the issue
    b. Create an action plan
    c. Implement the solution
    d. Determine the scope of the problem

Answer 15

a. Once you have determined that the switch or the configuration of the switch is the problem, you need to escalate the issue.

Question 16

16. A user calls you, complaining that he can’t access the corporate intranet web server. You try the same address, and you receive a “Host Not Found” error. Several minutes later, another user reports the same problem. You can still send email and transfer files to another server. What is the most likely cause of the problem?
    a. The hub is unplugged
    b. The server is not routing protocols to your workstation
    c. The user’s workstation is not connected to the network
    d. The web server is down

Answer 16

d. Because other people are experiencing the problem, most likely it is either network or server related. Because you can transfer files to and from another server, it can’t be the network. Thus, the problem is related to the web server.

Question 17

17. You have implemented and tested a solution and identified any other effects the solution may have. What is your next step?
    a. Create an action plan
    b. Close the case and head home for the day
    c. Reboot the Windows server
    d. Document the solution

Answer 17

d. After investigating the problem thoroughly and successfully testing and resolving an issue, you need to document the solution.

Question 18

18. Users are reporting that they can access the internet but not the internal company website. Which of the following is the most likely problem?
    a. The DNS entry for the server in non-authoritative
    b. The intranet server is down
    c. The DNS address handed out by DHCP is incorrect
    d. The default gateway is incorrect

Answer 18

b. Since users can get to the internet, this means the DNS server is working and they have the correct default gateway. The intranet server is probably down.

Question 19

19. Several users have complained about the server’s poor performance as of late. You know that the memory installed in the server is sufficient. What could you use to determine the source of the problem?
    a. Server’s NIC link light
    b. Protocol analyser
    c. Performance-monitoring tools
    d. Server’s system log file

Answer 19

c. Performance-monitoring tools can give you an idea of how busy the server and the rest of the network are. These tools use graphs to indicate how much traffic is going through the server.

Question 20

20. You lose power to your computer room and the switches in your network do not come back up when everything is brought online. After you have identified the affected areas, established the cause and escalated this problem, what do you do next?
    a. Start to implement a solution to get those users back online ASAP.
    b. Create an action plan and solution.
    c. Meet with the emergency response team to determine the next step.
    d. Copy all the working router’s configurations to the non-working switches

Answer 20

c. Once you escalate the problem, you are done with the seven-step model. Meet with the escalation team to determine the next step.