CompTIA Network+ Network+ Troubleshooting and Tools 2 — Questions and Answers
Question 1: A technician uses the 'netstat -an' command and sees many connections in a TIME_WAIT state. What does this indicate?
- Active connections that are transferring data
- Connections that have closed but are waiting for delayed packets to arrive (Correct answer)
- Connections that are waiting for the remote host to respond
- Connections blocked by the local firewall
Correct answer: Connections that have closed but are waiting for delayed packets to arrive
TIME_WAIT is a TCP state where a closed connection waits (typically 2x MSL) to ensure all delayed packets have been discarded.
Question 2: Which tool would best help a technician identify the path that packets take between a source and destination across the internet?
- nslookup
- traceroute/tracert (Correct answer)
- netstat
- arp
Correct answer: traceroute/tracert
Traceroute (tracert on Windows) sends packets with incrementing TTL values to map each hop along the network path.
Question 3: A user reports intermittent connectivity. A technician runs a continuous ping and observes occasional request timeouts. What is the most likely cause?
- DNS server is offline
- Packet loss on the network path (Correct answer)
- DHCP lease has expired
- MTU mismatch on the NIC
Correct answer: Packet loss on the network path
Intermittent ping timeouts indicate packet loss, which can be caused by a faulty cable, overloaded link, or failing network device.
Question 4: What does the 'arp -a' command display?
- All active TCP connections on the host
- The ARP cache mapping IP addresses to MAC addresses (Correct answer)
- All DNS records cached by the OS
- The routing table of the local host
Correct answer: The ARP cache mapping IP addresses to MAC addresses
The 'arp -a' command displays the ARP cache, which shows resolved IP-to-MAC address mappings for recently contacted devices.
Question 5: A cable tester shows a 'split pair' fault. What does this mean?
- Two wires are shorted together
- Wires from different pairs are connected at both ends creating crosstalk (Correct answer)
- One wire has a break causing an open circuit
- The cable length exceeds the 100m limit
Correct answer: Wires from different pairs are connected at both ends creating crosstalk
A split pair occurs when wires from different pairs are swapped at both ends; the cable tests as correctly wired but causes excessive crosstalk.
Question 6: Which command on a Windows system would release the current DHCP-assigned IP address?
- ipconfig /renew
- ipconfig /flushdns
- ipconfig /release (Correct answer)
- ipconfig /displaydns
Correct answer: ipconfig /release
'ipconfig /release' sends a DHCPRELEASE message to the server and removes the current IP address assignment from the interface.
Question 7: A technician suspects a duplicate IP address on the network. Which tool would most quickly confirm this?
- nslookup
- netstat
- arp -a (Correct answer)
- route print
Correct answer: arp -a
Checking the ARP cache with 'arp -a' can reveal if two different MAC addresses are mapped to the same IP, indicating a duplicate.
CompTIA Network+ Network+ Troubleshooting and Tools 2
A technician uses the 'netstat -an' command and sees many connections in a TIME_WAIT state.
What does this indicate?