The answer is a router. The ONT (Optical Network Terminal) converts the fiber optic signal into Ethernet, but it operates at Layer 1 and Layer 2 of the OSI model, meaning it cannot perform routing or Network Address Translation (NAT). A router placed between the ONT and the switch is essential because it handles IP addressing, routes traffic between the local network and the internet, and provides NAT to allow multiple devices to share a single public IP. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of network device roles—a common trap is choosing a switch, which only forwards frames within the same subnet, or a firewall, which secures but does not primarily route. Remember: the ONT gives you the line, but the router gives you the lane. A quick memory tip is “ONT to Router to Switch”—the router is the traffic cop that translates private addresses to public ones, making NAT possible.
220-1101 Common Networking Hardware Practice Question
This 220-1201 practice question tests your understanding of common networking hardware. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company is setting up a new branch office with 30 employees. They need to connect all workstations to the network and provide internet access. The internet connection is a fiber optic line terminating in an ONT. Which device should be placed between the ONT and the switch to route traffic and provide NAT?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Router
The ONT converts fiber to Ethernet, but it does not route or perform NAT. A router is required to connect the local network to the internet, provide NAT, and handle IP addressing. A switch alone cannot route, and a firewall is often combined with a router but is not the primary device for routing. The correct answer is a router.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Patch panel
Why it's wrong here
A patch panel is for cable management, not routing or NAT.
✓
Router
Why this is correct
A router connects the ONT to the switch, performs NAT, and routes traffic between the local network and the internet.
Related concept
Static NAT maps one inside address to one outside address.
✗
Layer 2 switch
Why it's wrong here
A Layer 2 switch forwards frames within the same network but cannot route between networks or perform NAT.
✗
Firewall appliance
Why it's wrong here
A firewall provides security but typically sits behind a router; it does not replace the routing function.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 220-1201 question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
Common Networking Hardware — This question tests Common Networking Hardware — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Router — The ONT converts fiber to Ethernet, but it does not route or perform NAT. A router is required to connect the local network to the internet, provide NAT, and handle IP addressing. A switch alone cannot route, and a firewall is often combined with a router but is not the primary device for routing. The correct answer is a router.
What should I do if I get this 220-1201 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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Question Discussion
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