220-1101 Networking Practice Question
A technician is setting up a small network. The modem from the ISP provides a single public IP address via DHCP. The technician needs to connect 10 computers to the internet using a single public IP. Which device should the technician install between the modem and the computers to accomplish this?
⚠ Common exam trap
Many exam-takers confuse a switch's ability to 'connect multiple devices' with the ability to share an internet connection, but a switch cannot perform NAT or routing—it only forwards traffic within the same subnet, requiring each device to have a public IP or a separate router for internet sharing.
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
✓
Router with NAT capabilities
The modem provides a single public IP address via DHCP, but 10 computers need internet access. A router with NAT (Network Address Translation) allows multiple devices to share that single public IP by translating their private IP addresses (e.g., 192.168.1.x) to the public IP for outbound traffic, and mapping return traffic back to the correct internal device. This is the standard solution for IPv4 address conservation in small networks.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Hub
Why it's wrong here
A hub is a Layer 1 device that simply receives a signal and broadcasts it out all other ports, without any awareness of IP addresses or network boundaries. Because it performs no address translation or packet inspection, every connected device would still need its own unique public IP address to communicate with the internet. A single ISP-provided public IP cannot be shared by multiple computers through a hub, as the hub cannot rewrite or translate addresses. Therefore, a hub is entirely unsuitable for this scenario.
- ✗
Switch
Why it's wrong here
A switch operates at Layer 2 and forwards Ethernet frames based on MAC addresses, building a MAC address table but remaining oblivious to IP addresses. While a switch can efficiently connect multiple devices in a local network, it does not provide Network Address Translation (NAT) or any form of IP masquerading. Consequently, without a router or NAT-capable device, each host on a switch would require its own public IP address from the ISP. Thus, a switch alone cannot enable multiple computers to share a single public IP.
- ✓
Router with NAT capabilities
Why this is correct
A router with NAT capabilities is the correct choice because it operates at Layer 3 and can translate private IP addresses to a single public IP address. NAT allows many devices on the LAN, such as 192.168.1.x, to all appear as the same public IP when connecting to the internet, by rewriting source addresses and port numbers in outgoing packets and maintaining a translation table for return traffic. This is precisely the functionality needed when an ISP provides only one public IP address, as the router makes that address shared among all network clients.
- ✗
Bridge
Why it's wrong here
A bridge connects two or more network segments at Layer 2 and forwards frames based on MAC addresses, similar to a switch but with a simpler design. It does not perform any Layer 3 functions, such as IP routing or NAT, so it cannot translate private addresses to a public one. Bridges are used to segment Ethernet networks and reduce collisions, but they are not internet-connection sharing devices. Therefore, a bridge would not allow multiple computers to share a single public IP address.
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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.