CompTIA Network+ (N10-009)Network TroubleshootingMedium
A technician runs a traceroute to a remote server and observes the following partial output for hops 8 through 10: '8 * * * Request timed out. 9 * * * Request timed out. 10 15 ms 14 ms 16 ms remote-server.com'. What does this output MOST likely indicate?
- AThe remote server is completely unreachable
- BHops 8 and 9 are configured to not respond to ICMP but still forward traffic
- CThe DNS server failed to resolve hops 8 and 9
- DThere is a routing loop between hops 8 and 9
Show answer & explanationAnswer & explanation
Correct answer: B. Hops 8 and 9 are configured to not respond to ICMP but still forward traffic
Asterisks in traceroute output typically mean a hop is not responding to ICMP/UDP probe packets, often because it is configured to block or rate-limit ICMP for security reasons, while still correctly forwarding the traffic onward. The fact that hop 10 replies successfully proves connectivity beyond those hops is intact.
Why the other options are wrong
- A. The server is clearly reachable since hop 10 responds successfully with round-trip times.
- C. Traceroute uses IP addresses for routing, and DNS resolution failure would show as an IP or unresolved name, not asterisks.
- D. A routing loop would show repeated hops or continuously increasing TTLs, not simple timeouts.
Traceroute Asterisks
Asterisks (*) in traceroute output indicate no response was received from a hop within the timeout window, often due to ICMP filtering.
- Traceroute uses TTL expiration and ICMP Time Exceeded messages to map the path
- Many routers/firewalls silently drop or deprioritize ICMP without blocking actual traffic
- A successful response at a later hop confirms the path continues normally despite silent hops
Memory trick: Silent hops don't mean broken hops