N10-009 Network Troubleshooting Practice Question
A network technician runs the command "traceroute 8.8.8.8" from a workstation. The output shows the first hop as the default gateway, the second hop as an internal router, and then a series of asterisks (* * *) before reaching the destination. What does the series of asterisks indicate?
⚠ Common exam trap
The N10-009 exam often tests the misconception that asterisks mean the destination is unreachable, but the key is that traceroute still reaches the final hop, so the asterisks only indicate missing ICMP responses from intermediate routers, not a failure to reach the target.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The intermediate routers are not responding to ICMP time-exceeded messages
The series of asterisks indicates that intermediate routers beyond the second hop are not responding with ICMP Time-Exceeded messages when the TTL expires. Traceroute relies on these ICMP responses to identify each hop; if a router is configured to drop ICMP or not send the message, the output shows asterisks for that hop. The destination is still reachable, as the final hop succeeds, so the asterisks do not indicate unreachability.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The destination is unreachable
Why it's wrong here
If the destination were truly unreachable, the traceroute command would typically terminate with an "Destination Host Unreachable" message, often accompanied by ICMP Destination Unreachable messages from a router along the path, rather than showing asterisks for intermediate hops and then successfully reaching the final destination. The presence of asterisks for intermediate hops, while still ultimately reaching 8.8.8.8, indicates that the path to the destination exists and is traversable, but specific routers are not responding to the ICMP probes.
When this WOULD be correct
In a question where traceroute output shows asterisks at the final hop and no response from the destination, option A would be correct. For example: 'A traceroute to a remote server shows asterisks at the last hop and no final reply. What does this indicate?'
- ✓
The intermediate routers are not responding to ICMP time-exceeded messages
Why this is correct
Traceroute works by sending packets with incrementally increasing Time-to-Live (TTL) values. When a router receives a packet with a TTL of 1, it decrements it to 0 and, by protocol, should send an ICMP Time Exceeded message back to the source. Asterisks in traceroute output signify that an intermediate router failed to send this expected ICMP response, often because its firewall is configured to drop such messages or due to rate limiting to prevent denial-of-service attacks, rather than forwarding them. This prevents the traceroute utility from identifying that specific hop.
- ✗
The TTL expired at the last hop
Why it's wrong here
If the Time-to-Live (TTL) expired at the last hop *before* reaching the ultimate destination, the traceroute would typically show asterisks for that hop, indicating no response, and subsequent hops would also likely fail to resolve. However, the problem statement implies the `traceroute 8.8.8.8` command was run, and 8.8.8.8 is a reachable destination. If the TTL expired at the *actual* destination, the destination itself would respond with an ICMP Port Unreachable or similar message, not just asterisks, because the packet successfully arrived.
- ✗
The connection is encrypted
Why it's wrong here
Network connection encryption, such as SSL/TLS or IPsec, operates at higher layers of the OSI model (transport/session/presentation or network layer for IPsec payload). Traceroute, however, relies on the Internet Control Message Protocol (ICMP) and the Time-to-Live (TTL) field within the IP header, which are fundamental network layer (Layer 3) functions. Encryption of the data payload does not interfere with a router's ability to decrement the TTL and send an ICMP Time Exceeded message, making it irrelevant to the appearance of asterisks in traceroute output.
When this WOULD be correct
When a question asks what could cause a traceroute to show asterisks if the path uses encrypted tunnels that drop ICMP packets, or if the destination requires encrypted communication and the traceroute packets are blocked.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓The intermediate routers are not responding to ICMP time-exceeded messagesCorrect answer▾
Why this is correct
Traceroute works by sending packets with incrementally increasing Time-to-Live (TTL) values. When a router receives a packet with a TTL of 1, it decrements it to 0 and, by protocol, should send an ICMP Time Exceeded message back to the source. Asterisks in traceroute output signify that an intermediate router failed to send this expected ICMP response, often because its firewall is configured to drop such messages or due to rate limiting to prevent denial-of-service attacks, rather than forwarding them. This prevents the traceroute utility from identifying that specific hop.
✗The destination is unreachableWrong answer — click to see why▾
Why this is wrong here
A series of asterisks in traceroute indicates that ICMP time-exceeded messages were not received from intermediate routers, not that the destination is unreachable. The destination (8.8.8.8) is reached, as shown by the final hop completing.
★ When this WOULD be the correct answer
In a question where traceroute output shows asterisks at the final hop and no response from the destination, option A would be correct. For example: 'A traceroute to a remote server shows asterisks at the last hop and no final reply. What does this indicate?'
Why candidates choose this
Candidates may assume that asterisks mean a failure to reach the destination, confusing a lack of response from intermediate hops with a complete unreachability of the target.
✗The connection is encryptedWrong answer — click to see why▾
Why this is wrong here
Encryption does not affect traceroute's ability to receive ICMP time-exceeded messages; asterisks indicate lack of response, not encryption.
★ When this WOULD be the correct answer
When a question asks what could cause a traceroute to show asterisks if the path uses encrypted tunnels that drop ICMP packets, or if the destination requires encrypted communication and the traceroute packets are blocked.
Why candidates choose this
Candidates may confuse encryption with packet filtering or assume that encrypted paths hide intermediate hops, leading them to incorrectly attribute asterisks to encryption.
Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
Learn chapter
Troubleshoot: Network Connectivity
Key term
ICMP
ICMP is a network protocol used by devices to send error messages and operational information about network communication problems.
Key term
Traceroute
Traceroute is a network diagnostic tool that maps the route data packets take from your computer to a destination, showing each intermediate hop and the time taken.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This N10-009 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the N10-009 exam.