Troubleshooting Practice Questions: Networking Fundamentals

1. A small office network uses a device that connects all computers in a star topology and forwards data packets only to the port where the destination device is connected, rather than broadcasting to all ports. Which device is MOST likely being used?
(a) Hub
(b) Switch
(c) Repeater
(d) Bridge

2. What is the maximum cable length for a Cat6 Ethernet cable to maintain 1000BASE-T speeds without signal degradation?
(a) 100 feet
(b) 328 feet
(c) 500 feet
(d) 656 feet

3. A technician is troubleshooting a network connection issue on a Windows 10 workstation. The user reports they cannot access any websites, but the network icon shows connected. Running ipconfig shows an IP address of 169.254.12.45. What is the MOST likely cause of this problem?
(a) DNS server is unavailable
(b) Default gateway is misconfigured
(c) DHCP server is not reachable
(d) Network adapter driver is corrupted

4. An office administrator reports that file transfers between two computers on the local network are extremely slow, taking several minutes for small documents. Both computers show connected at 1 Gbps in their network adapter properties, and other network activities seem normal. Which tool should the technician use FIRST to identify potential cabling issues?
(a) Multimeter
(b) Tone generator and probe
(c) Cable tester
(d) Loopback plug

5. Which TCP/IP protocol is responsible for automatically assigning IP addresses to network devices?
(a) DNS
(b) ARP
(c) DHCP
(d) ICMP

6. A network technician needs to create a crossover cable to directly connect two legacy switches without an uplink port. Which wiring standard combination should be used on each end of the cable?
(a) T568A on both ends
(b) T568A on one end and T568B on the other end
(c) T568B on both ends
(d) T568C on one end and T568A on the other end

7. A company's IT department is setting up a new conference room with wireless connectivity. They need to ensure the wireless network can handle multiple high-definition video conferences simultaneously with minimal interference. The area has several 2.4 GHz networks from neighboring businesses. Which wireless standard and frequency combination would be BEST for this scenario?
(a) 802.11n on 2.4 GHz
(b) 802.11g on 2.4 GHz
(c) 802.11ac on 5 GHz
(d) 802.11b on 2.4 GHz

8. A user calls the help desk stating their laptop cannot connect to the corporate wireless network after returning from a business trip. The laptop successfully connects to their home Wi-Fi and other public networks. The wireless icon shows the corporate SSID but displays "Can't connect to this network" on Windows 11. What should the technician instruct the user to do FIRST?
(a) Update the wireless adapter driver
(b) Disable and re-enable the wireless adapter
(c) Forget the network and reconnect with credentials
(d) Reset the TCP/IP stack using netsh commands

9. Which port number does the HTTPS protocol use by default for secure web communications?
(a) 80
(b) 21
(c) 25
(d) 443

10. A network administrator is troubleshooting intermittent connectivity issues in a newly installed office network. Several users report that their connections drop briefly every few minutes. Upon inspection, the administrator discovers that some Ethernet cables run parallel to fluorescent lighting fixtures for approximately 15 feet. What is the MOST likely cause of the connectivity problems?
(a) Attenuation from excessive cable length
(b) Electromagnetic interference from the lighting
(c) Incorrect cable termination
(d) Duplex mismatch on the switch ports

11. A technician needs to verify end-to-end network connectivity to a remote web server and measure the round-trip time for packets. Which command-line utility should be used?
(a) netstat
(b) tracert
(c) ping
(d) nslookup

12. An employee working from home reports that video calls freeze frequently, but web browsing and email work fine. The ISP provides 100 Mbps download and 10 Mbps upload speeds. A speed test confirms these speeds, and the router shows a strong Wi-Fi signal. What is the MOST likely explanation for the video call quality issues?
(a) Insufficient download bandwidth
(b) DNS resolution delays
(c) High network latency or jitter
(d) Firewall blocking video traffic

13. A server administrator configures a server with IP address 192.168.10.50 and subnet mask 255.255.255.0. What is the network address for this configuration?
(a) 192.168.10.0
(b) 192.168.0.0
(c) 192.168.10.255
(d) 192.168.10.1

14. A small business owner wants to allow employees to access the office file server remotely over the internet but is concerned about security. The owner mentions that port 3389 is currently forwarded through the firewall. What recommendation should the technician make to improve security while maintaining remote access functionality?
(a) Change RDP to use port 80 instead
(b) Implement a VPN solution and close the forwarded port
(c) Enable WPA3 encryption on the wireless network
(d) Install antivirus software on all client computers

15. During network troubleshooting, a technician runs the command "ipconfig /all" on a Windows workstation and notices the default gateway address is blank. The computer has a valid static IP address of 10.0.50.25 with subnet mask 255.255.255.0. Users report they can access other computers on the local network but cannot reach the internet or any external resources. What configuration change is needed?
(a) Configure a DNS server address
(b) Change to DHCP instead of static IP
(c) Add the router's IP address as the default gateway
(d) Modify the subnet mask to 255.255.0.0

16. Which of the following IPv6 addresses represents a link-local address automatically configured by the operating system?
(a) 2001:db8:0:1::1
(b) fe80::a1b2:c3d4:e5f6:7890
(c) ff02::1
(d) ::1

17. A technician is setting up QoS (Quality of Service) on a corporate network router to prioritize certain types of traffic during peak hours. Management wants to ensure VoIP phone calls maintain quality even when the network is congested with file transfers and web browsing. Which network characteristic is the QoS configuration primarily designed to manage?
(a) Bandwidth allocation and packet prioritization
(b) Encryption strength for secure communications
(c) IP address assignment and DHCP scope
(d) MAC address filtering and access control

18. A user reports that websites load very slowly on their desktop computer, often timing out before fully loading. Other users on the same network segment have no issues. The technician verifies the computer has correct IP settings and strong physical connectivity. Running "nslookup google.com" takes 8-10 seconds to return results. What should the technician do to resolve this issue?
(a) Replace the network cable
(b) Configure alternative DNS server addresses
(c) Increase the network adapter's speed setting
(d) Disable IPv6 on the network adapter

19. A network administrator needs to determine which intermediate routers a packet traverses between the local workstation and a destination server experiencing connectivity issues. Which command will show the path and response time at each hop?
(a) ping -t
(b) netstat -r
(c) tracert
(d) ipconfig /displaydns

20. A company implements a network security policy requiring all wireless access points to use WPA3-Enterprise authentication. New employees complain they cannot connect their personal smartphones to the corporate wireless network, receiving authentication errors. Their devices successfully connect to home networks using WPA2-Personal. What additional configuration is required on the employee devices to connect to the corporate network?
(a) Install the latest wireless driver updates
(b) Configure 802.1X credentials with username and password
(c) Change the wireless adapter to use 5 GHz only
(d) Enable MAC address randomization in device settings