FC0-U71 Infrastructure Practice Question
A small business wants to connect its office to a fiber internet service. The ISP provides an optical network terminal (ONT) that converts the fiber signal to Ethernet. The business needs a device that will route traffic between the internal LAN and the ISP, perform NAT, and provide DHCP to internal clients. Which device should the technician install between the ONT and the LAN switch?
⚠ Common exam trap
Test-takers frequently confuse the ONT's media conversion role with routing, and assuming that because the ONT outputs Ethernet, any Ethernet device can connect the LAN to the ISP.
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
✓
A router
The device between an ONT and an internal switch must route packets, translate private addresses to the public address, and assign IP configuration to clients. A router provides all three functions at Layer 3. Switches, access points, and media converters operate at lower layers or serve different purposes and cannot fulfill the routing and NAT requirements of this scenario.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A media converter
Why it's wrong here
A media converter changes one physical medium to another, such as fiber to copper Ethernet, but it does not make routing decisions or provide IP services. Since the ONT already converts fiber to Ethernet, an additional media converter adds no value. It cannot perform NAT or DHCP, so it would not allow the internal LAN to share the ISP connection or receive automatic IP addressing.
- ✗
A Layer 2 switch
Why it's wrong here
A Layer 2 switch forwards frames based on MAC addresses within a single broadcast domain. It does not perform NAT, DHCP server functions, or routing between the private LAN and the public ISP network. While it can connect the ONT and internal devices physically, it cannot translate private addresses or hand out IP configuration, so it would not meet the requirement for internet sharing and internal addressing.
- ✓
A router
Why this is correct
A router operates at Layer 3 and forwards packets between the private LAN and the ISP network. It performs NAT to translate private addresses to the public address provided by the ISP, runs a DHCP server to assign IP configuration to internal clients, and often includes a firewall. Placing a router between the ONT and the LAN switch provides the routing, NAT, and DHCP functions the business requires.
- ✗
A wireless access point
Why it's wrong here
A wireless access point bridges wireless clients onto an existing wired network but does not route, perform NAT, or act as a DHCP server for a LAN. It relies on an upstream router for those services. Installing only an access point between the ONT and the switch would leave the network without address translation and dynamic IP assignment, so clients could not reach the internet through the fiber connection.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
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.