Troubleshooting Practice Questions: Network Troubleshooting

1. A user reports that they cannot access any websites on their laptop, but other users on the same wireless network are browsing normally. The user's laptop shows a strong Wi-Fi signal and appears to be connected to the network. Which command should a technician run FIRST to diagnose the issue?
(a) nslookup
(b) ipconfig /all
(c) netstat -a
(d) tracert

2. Which of the following tools would BEST help a technician determine if a network cable is properly terminated and identify which standard was used?
(a) Multimeter
(b) Loopback plug
(c) Cable tester
(d) Toner probe

3. An employee in a corporate office complains that their desktop computer intermittently loses network connectivity throughout the day. A technician notices that the connection drops only when the cleaning crew uses a vacuum cleaner near the employee's desk. The computer is connected via Ethernet cable. What is the MOST likely cause?
(a) The vacuum is causing electromagnetic interference with an unshielded cable
(b) The vacuum is drawing too much power from the same electrical circuit
(c) The network switch is overheating during peak usage times
(d) The Ethernet port on the computer is failing

4. A technician receives a trouble ticket stating that a user cannot print to a network printer. The user can access websites and send emails without issue. Which of the following should the technician check FIRST?
(a) Whether the printer is powered on and shows ready status
(b) Whether the user's computer has the correct IP address
(c) Whether the network switch port is functioning
(d) Whether the firewall is blocking port 80

5. A small office has five computers that suddenly cannot access the internet, though they can still access shared folders on the local file server. The office uses a cable modem connected to a router. Which component is MOST likely causing the issue?
(a) Network switch
(b) Cable modem or ISP connection
(c) Wireless access point
(d) DNS server on the local network

6. What is the default subnet mask for a Class C IP address?
(a) 255.255.0.0
(b) 255.255.255.0
(c) 255.0.0.0
(d) 255.255.255.255

7. A technician is troubleshooting a laptop that displays "Limited or No Connectivity" in Windows 10. Running ipconfig shows the laptop has an IP address of 169.254.12.45. The user reports they were connected to the network yesterday without issues. What should the technician do NEXT?
(a) Manually assign a static IP address to the laptop
(b) Check the DHCP server availability and network cable connection
(c) Disable and re-enable the wireless adapter
(d) Run netstat to check for active connections

8. A network administrator is troubleshooting slow file transfers between two buildings connected by a fiber optic cable. The connection was working at full speed last week, but now transfers are significantly slower. Using a light meter, the technician discovers signal loss beyond acceptable levels. What is the MOST likely cause?
(a) A bend in the fiber optic cable exceeding the minimum bend radius
(b) Electromagnetic interference from nearby electrical equipment
(c) Incorrect subnet mask configuration on both ends
(d) DNS resolution delays

9. Which TCP/IP utility would BEST help identify the specific router or hop where packet loss is occurring along a network path?
(a) ping
(b) ipconfig
(c) pathping
(d) nslookup

10. A user in a large corporate environment reports they can access the company intranet and most internal resources, but cannot reach a specific database server at IP address 10.50.25.100. Other users in different departments can access this database without problems. The technician pings the server from the user's workstation and receives "Request timed out." What should the technician check FIRST?
(a) Whether the user's workstation has firewall rules blocking the database port
(b) Whether the database server is online and responding
(c) Whether the user has the correct permissions in Active Directory
(d) Whether there is a VLAN configuration issue affecting the user's subnet

11. A technician is setting up a new office and needs to create a cable to connect a laptop directly to a desktop computer for file transfer without using a switch. Which type of cable should be used?
(a) Straight-through cable
(b) Rollover cable
(c) Crossover cable
(d) Plenum cable

12. A help desk receives multiple calls from users in a specific department reporting they cannot access network resources. A technician checks the network switch and discovers that port 15, which connects to another switch serving that department, has an amber LED lit instead of green. What does this indicator MOST likely mean?
(a) The port is functioning normally at 100 Mbps
(b) There is a connectivity problem or link failure on that port
(c) The port is operating in full-duplex mode
(d) Power over Ethernet is being supplied through that port

13. A remote worker using a VPN connection reports extremely slow performance when accessing company resources, though their internet speed test shows normal download and upload speeds. The user is connected via Wi-Fi to their home router. Which action should the technician recommend FIRST to improve VPN performance?
(a) Connect the computer to the router using an Ethernet cable
(b) Upgrade the company's VPN server hardware
(c) Change the Wi-Fi channel on the home router
(d) Increase the MTU size on the VPN connection

14. During network troubleshooting, a technician successfully pings 127.0.0.1 but cannot ping the computer's assigned IP address. What does this indicate?
(a) The default gateway is unreachable
(b) The DNS server is not responding
(c) The network adapter or its driver has a problem
(d) The DHCP server is offline

15. A company has recently expanded its wireless network by adding three new access points. Users near these new access points report frequent disconnections and slow speeds, while users near the original access points experience no issues. All access points are configured with the same SSID and security settings. What is the MOST likely cause of the problem?
(a) The new access points are using overlapping channels with the existing ones
(b) The new access points have faulty antennas
(c) The DHCP server has run out of available IP addresses
(d) The new access points are using WPA2 instead of WPA3

16. A technician needs to verify that a computer can resolve domain names to IP addresses. Which command should be used to test DNS functionality directly?
(a) ping google.com
(b) tracert 8.8.8.8
(c) nslookup google.com
(d) netstat -r

17. An office building experiences a complete network outage affecting all 50 workstations. The technician discovers that the main network switch has no power, and the UPS unit that protects it is beeping with a solid red light. All other equipment on different UPS units is functioning normally. What should the technician do FIRST?
(a) Replace the failed UPS battery immediately
(b) Connect the switch to a different power source to restore network service
(c) Contact the ISP to report the outage
(d) Check individual workstation network settings

18. A user reports that websites load very slowly, taking 30-45 seconds to display, but once loaded, browsing between pages on the same site is fast. Email and file transfers work normally. The technician pings several websites successfully with normal response times. Which component is MOST likely causing the delay?
(a) The user's network adapter
(b) The DNS server
(c) The default gateway
(d) The web browser cache

19. A network technician is troubleshooting connectivity issues in a conference room where multiple users report intermittent wireless disconnections during meetings. The technician uses a Wi-Fi analyzer and discovers several other wireless networks operating on channels 1, 6, and 11, all with strong signals. The company's access point is currently on channel 6. What should the technician do to resolve this issue?
(a) Increase the transmission power of the company's access point
(b) Change the access point to channel 3 to avoid interference
(c) Switch to the 5 GHz band if supported by the access point and client devices
(d) Enable MAC address filtering on the access point

20. A technician is documenting a network topology and needs to identify which physical ports on a patch panel correspond to specific wall jacks in various offices. The offices are occupied and the technician cannot disrupt network service. Which tool would be MOST appropriate for this task?
(a) Cable tester
(b) Multimeter
(c) Toner probe
(d) Loopback plug