CompTIA Network+ Network+ Troubleshooting and Tools 3 — Questions and Answers
Question 1: A technician uses a toner probe kit. What is the primary purpose of this tool?
- Testing cable speed and throughput
- Locating and tracing a specific cable through walls or a patch panel (Correct answer)
- Measuring signal attenuation over a cable run
- Detecting open and short circuits in a cable
Correct answer: Locating and tracing a specific cable through walls or a patch panel
A toner probe (tone generator and probe) is used to identify and trace the path of a specific cable among many others.
Question 2: Which of the following symptoms is most characteristic of a broadcast storm?
- Slow DNS resolution across all clients
- Sudden complete network performance collapse affecting all devices (Correct answer)
- One workstation unable to reach a specific subnet
- Wireless clients dropping to slower 802.11g speeds
Correct answer: Sudden complete network performance collapse affecting all devices
A broadcast storm causes exponentially increasing broadcast traffic that saturates the entire network, causing complete performance collapse for all devices.
Question 3: What does a high number of CRC errors on a switch port most likely indicate?
- The connected device has a misconfigured VLAN
- Physical layer issues such as a faulty cable or NIC (Correct answer)
- IP address conflict on the subnet
- MTU black hole between routers
Correct answer: Physical layer issues such as a faulty cable or NIC
CRC errors indicate corrupted frames arriving at the switch port, most commonly caused by physical media problems like a bad cable or failing NIC.
Question 4: A technician needs to capture and analyze network packets in real time. Which tool is best suited for this?
- Nmap
- Wireshark (Correct answer)
- Nessus
- SolarWinds NPM
Correct answer: Wireshark
Wireshark is a packet analyzer (protocol analyzer) that captures and displays network traffic in real time for detailed inspection.
Question 5: An administrator notices the network is slow only during business hours. Which tool would best help identify which application or host is consuming the most bandwidth?
- Ping
- Protocol analyzer / bandwidth monitor (Correct answer)
- Cable tester
- OTDR
Correct answer: Protocol analyzer / bandwidth monitor
A bandwidth monitor or protocol analyzer (e.g., SNMP-based tools or NetFlow) can identify top talkers and applications consuming bandwidth over time.
Question 6: What is the purpose of an OTDR (Optical Time-Domain Reflectometer)?
- Measuring wireless signal strength at various locations
- Testing and locating faults in fiber optic cables (Correct answer)
- Capturing Ethernet frames for protocol analysis
- Verifying copper cable pinout and continuity
Correct answer: Testing and locating faults in fiber optic cables
An OTDR sends light pulses into a fiber cable and analyzes reflections to locate breaks, splices, connectors, and measure loss.
Question 7: A user can ping a server by IP address but not by hostname. What is the most likely cause?
- The server's NIC is failing
- DNS resolution is failing for that hostname (Correct answer)
- The default gateway is misconfigured
- DHCP is not assigning the correct subnet mask
Correct answer: DNS resolution is failing for that hostname
If IP connectivity works but hostname resolution fails, the issue is with DNS — the name is not resolving to the correct IP address.
CompTIA Network+ Network+ Troubleshooting and Tools 3
A technician uses a toner probe kit.
What is the primary purpose of this tool?