hardMultiple Choice
FC0-U71 Practice Question: A small business has a single server running…
A small business has a single server running Windows Server 2019 that acts as a domain controller, file server, and DHCP server. The server has a single network interface with IP address 192.168.1.10/24. The office has 30 client computers running Windows 10. All clients obtain IP addresses automatically. The network uses a single unmanaged switch. The internet connection is provided by a cable modem with IP 192.168.1.1. The server is configured with a static IP of 192.168.1.10, and the DHCP scope is 192.168.1.100-192.168.1.200. Recently, users have reported that they cannot access the internet. The technician checks that the cable modem is online and that the server can ping the modem. The technician runs 'ipconfig /all' on a client and sees: IP: 192.168.1.101, Subnet: 255.255.255.0, Default Gateway: 192.168.1.10, DNS: 192.168.1.10. The client can ping the server (192.168.1.10) but cannot ping the modem (192.168.1.1). What is the most likely cause?
⚠ Common exam trap
Test-takers frequently assume the server can act as a router because it is a domain controller and file server, but without enabling routing services (like RRAS), the server will not forward traffic between subnets or to the internet.
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
✓
Change the DHCP scope option for the default gateway to 192.168.1.1
The DHCP scope is configured with the default gateway option set to 192.168.1.10 (the server's IP), but the actual default gateway for internet access is the cable modem at 192.168.1.1. Since clients receive their gateway via DHCP, they are sending all off-subnet traffic to the server, which is not configured to route to the internet. Changing the DHCP scope option for the default gateway to 192.168.1.1 will allow clients to route internet traffic through the modem.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Disable the Windows Firewall on the server to allow traffic
Why it's wrong here
Disabling the server firewall does not address the client's inability to ping 192.168.1.1, because the client's default gateway points to 192.168.1.10, so its packets never reach the modem. It is tempting because firewalls block traffic, and this would be correct if the server were dropping forwarded packets while routing correctly.
- ✗
Replace the cable modem as it is not routing traffic correctly
Why it's wrong here
The modem is reachable from the server, proving it routes correctly, so replacing it cannot resolve the client's failed ping to 192.168.1.1. It is tempting because modem faults commonly cause internet outages, and replacement would be correct if the modem were genuinely failing to forward traffic.
- ✗
Configure the DNS server to forward queries to 8.8.8.8
Why it's wrong here
DNS forwarding to 8.8.8.8 cannot fix the failure, since the client cannot even ping the modem at 192.168.1.1, a layer-3 reachability problem independent of name resolution. It is tempting because DNS misconfiguration commonly breaks internet access, and forwarding would be correct if pings to the gateway succeeded but names failed.
- ✓
Change the DHCP scope option for the default gateway to 192.168.1.1
Why this is correct
The DHCP scope currently hands out 192.168.1.10 as the default gateway, so clients route all off-subnet traffic to the server, which is not a router and cannot forward it to the modem. Setting the gateway to 192.168.1.1 restores correct next-hop routing for internet access.
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.