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220-1201 Practice Question: A network administrator is configuring a small…
A network administrator is configuring a small business network with two subnets: 192.168.1.0/24 for employees and 192.168.2.0/24 for guests. The router has two LAN interfaces with IPs 192.168.1.1 and 192.168.2.1. A technician connects a new access point to the guest subnet switch and configures it with a static IP of 192.168.2.50. The access point can ping the router's guest interface but cannot reach the internet. The router's default route points to an ISP modem at 203.0.113.1. What is the most likely missing configuration?
⚠ Common exam trap
The 220-1201 exam often tests the misconception that a successful ping to the default gateway implies full internet connectivity, when in fact NAT misconfiguration is the hidden culprit that breaks traffic beyond the local router.
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
✓
NAT is not enabled for the 192.168.2.0/24 subnet on the router.
The access point can ping the router's guest interface (192.168.2.1), confirming Layer 2 and Layer 3 connectivity within the guest subnet. However, it cannot reach the internet, which indicates that the router is not performing Network Address Translation (NAT) for the 192.168.2.0/24 subnet. Without NAT, private IP addresses from the guest subnet are not translated to the router's public IP, so the ISP modem drops the return traffic because it has no route back to the private range.
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 access point's default gateway is set to 192.168.1.1.
Why it's wrong here
The access point is part of the 192.168.2.0/24 guest subnet, meaning its default gateway must be the router's interface on that same subnet, which is 192.168.2.1. If its gateway were incorrectly set to 192.168.1.1, it would be unable to route any traffic outside its local subnet, including pinging 192.168.2.1. Since the access point successfully pings the router's guest interface, its gateway configuration is likely correct, making this option invalid.
- ✓
NAT is not enabled for the 192.168.2.0/24 subnet on the router.
Why this is correct
Network Address Translation (NAT) is a critical router function that translates private IP addresses from internal networks, such as the 192.168.2.0/24 guest subnet, into a single public IP address for internet access. Without NAT enabled for this specific subnet, the router will drop or fail to forward packets originating from guest devices to the internet because they lack a valid public source IP. This precisely explains why guest devices cannot reach the internet, while employee devices, presumably with NAT configured, can.
- ✗
The access point has a duplicate IP address.
Why it's wrong here
A duplicate IP address on a network segment creates severe communication conflicts, as multiple devices attempt to claim the same network identity, leading to unpredictable behavior and connection failures. If the access point had a duplicate IP, it would experience intermittent connectivity or complete communication failure, making it highly unlikely to successfully ping the router's guest interface. The ability of the access point to ping the router confirms its IP address is unique and functional, discrediting this as the root cause.
- ✗
The ISP modem is blocking traffic from the guest subnet.
Why it's wrong here
The ISP modem primarily functions as a bridge between the local network router and the internet service provider's network, operating at a layer that typically only sees the router's public IP address. It does not inspect or filter traffic based on internal private IP subnets like 192.168.2.0/24, as that is the responsibility of the local router's firewall and routing configurations. Therefore, the modem is highly unlikely to be the component blocking specific internal guest subnet traffic from reaching the internet.
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Related to this question
Learn chapter
Mobile Device Connectivity
Key term
LAN
Local Area Network — a network confined to a single physical location such as an office, building, or campus.
Key term
Default route
A default route is a catch-all routing entry that tells a network device where to send packets when no specific route matches the destination address.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 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 220-1201 exam.