CNX-001 Question #83: Real Exam Question with Answer & Explanation

The correct answer is B: ICMP rate limiting or firewall block. Traceroute relies on ICMP Time Exceeded (or UDP/TCP responses depending on mode). If a router/firewall blocks or rate-limits ICMP, that hop won’t respond, and you’ll see *. Importantly, this doesn’t always mean traffic is failing-just that the hop isn’t sending traceroute replies

Cloud Network Operations and Troubleshooting

Question

When analyzing traceroute output, what does a consistent timeout ("* * *") at a specific hop indicate?

Options

ADNS misconfiguration
BICMP rate limiting or firewall block
CPacket fragmentation
DMTU discovery failure

Explanation

Traceroute relies on ICMP Time Exceeded (or UDP/TCP responses depending on mode). If a router/firewall blocks or rate-limits ICMP, that hop won’t respond, and you’ll see * * *. Importantly, this doesn’t always mean traffic is failing-just that the hop isn’t sending traceroute replies.

Topics

#Traceroute analysis#ICMP#Network troubleshooting#Firewall rules

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