mediumMultiple Choice
FC0-U71 Practice Question: Refer to the exhibit
Exhibit
IPv4 Address: 192.168.1.10 Subnet Mask: 255.255.255.0 Default Gateway: 192.168.1.1
Refer to the exhibit. A user on this computer can browse the internet but cannot ping another computer at 192.168.1.20. What is the most likely cause?
⚠ Common exam trap
A common mix-up: candidates assume a failed ping always indicates a network connectivity problem, but CompTIA tests the understanding that ICMP can be selectively blocked by a firewall while other traffic continues to work.
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
✓
A firewall is blocking ICMP traffic
The user can browse the internet, which confirms that the default gateway, DNS resolution, and subnet mask are correctly configured. However, the ping command fails specifically to 192.168.1.20, a local address. This indicates that ICMP traffic (used by ping) is being blocked, most likely by a firewall on the target computer or an intermediate device, while other traffic (HTTP/HTTPS) is permitted.
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 default gateway is incorrect
Why it's wrong here
Internet browsing already proves the default gateway is reachable and correct, since traffic leaves the local subnet through it. A wrong gateway would break external access too. It is tempting because a bad gateway does stop remote connectivity, but only beyond the local network, not to a same-subnet host.
- ✗
The DNS server is unreachable
Why it's wrong here
DNS resolution is irrelevant to ping, which requires only IP connectivity and ICMP; an unreachable DNS server would break name resolution, not a numeric-address ping. It is tempting because browsing works, suggesting name resolution is fine, yet the failure is at the ICMP or firewall layer.
- ✓
A firewall is blocking ICMP traffic
Why this is correct
A firewall blocking ICMP traffic explains why browsing succeeds while ping to 192.168.1.20 fails: web traffic uses TCP ports 80/443, which the firewall permits, whereas ping relies on ICMP echo requests, which many host or network firewalls drop by default. This satisfies the stem's constraint of internet access working alongside failed ping.
- ✗
The subnet mask is wrong
Why it's wrong here
A wrong subnet mask would also disrupt internet browsing, since the host could not correctly determine which destinations are local versus remote. Browsing works, so the mask is functional. It is tempting because mask errors do cause selective ping failures, but they would not spare external traffic.
Visual reference
Go deeper
Related to this question
About these practice questions
Courseiva writes every FC0-U71 question from scratch — 988 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This FC0-U71 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 FC0-U71 exam.