220-1101 Networking Practice Question
A technician is setting up a small office network. The router is connected to the ISP modem and has a public IP address on its WAN interface. The router's LAN is configured with DHCP on the 192.168.1.0/24 subnet. A workstation obtains an IP address of 192.168.1.10, subnet mask 255.255.255.0, and default gateway 192.168.1.1 from the router. The workstation can ping the gateway and other workstations on the same subnet, but it cannot access websites by IP address or domain name. Which of the following is the most likely cause?
⚠ Common exam trap
CompTIA often tests the distinction between local LAN connectivity and internet access, trapping candidates who assume a working gateway and DHCP mean full internet connectivity, when in fact NAT must be explicitly enabled for private-to-public address translation.
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
✓
Network Address Translation (NAT) is not enabled on the router.
The workstation can ping the gateway and local devices, indicating Layer 2/3 connectivity within the LAN is functional. However, it cannot reach external websites by IP or domain name, which points to a failure in translating private IP addresses to the public IP on the WAN interface. Network Address Translation (NAT) is required on the router to map the private 192.168.1.0/24 subnet to the public IP; without it, packets from the workstation have no routable source address on the internet, so responses cannot return.
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 workstation's DNS server is not configured correctly.
Why it's wrong here
An incorrectly configured DNS server would only break hostname-to-IP resolution, not direct IP connectivity. Since the user cannot reach websites by entering their IP address either, the problem lies outside DNS. The ability to ping the gateway and other local devices further confirms that IP-level routing is working, making DNS misconfiguration a symptom, not the cause.
- ✗
The workstation's subnet mask is incorrect.
Why it's wrong here
The workstation received a subnet mask of 255.255.255.0 from DHCP, which is appropriate for a /24 LAN like 192.168.1.0/24. With that mask, the workstation can successfully communicate with other local devices, which proves the mask is consistent with the network topology. An incorrect subnet mask would typically cause local and gateway communication to fail, so this cannot be the root cause.
- ✓
Network Address Translation (NAT) is not enabled on the router.
Why this is correct
NAT is the router process that translates private RFC 1918 addresses like 192.168.1.x into the router's public IP address for internet traversal. Without NAT, the workstation's private source address is not routable on the public internet, so responses never come back—even if the default gateway, DNS, and local connectivity are all perfect. NAT (specifically NAPT/PAT) must be enabled on the router to allow multiple internal devices to share a single public IP.
- ✗
The default gateway is incorrect.
Why it's wrong here
The default gateway is the router's LAN IP address, 192.168.1.1, and the workstation can successfully ping it. If the gateway were misconfigured, that ping would fail because the workstation would be trying to send packets to an unreachable or nonexistent address. Since the workstation can reach the gateway, the gateway is correctly set and cannot be the reason internet traffic fails.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 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 220-1101 exam.