220-1101 Question 107
Single answer2.4 Explain common network configuration concepts.A technician is configuring a small office's new network. The ISP provided a modem/router with the LAN set to 192.168.1.1/24 and DHCP enabled. The office already has a wireless router that will be used only to provide Wi-Fi access for employees, and the technician wants all devices to receive IP addresses from the ISP router and remain on the same subnet. Which configuration should the technician apply to the wireless router?
- A
Connect the ISP router to the wireless router's WAN port and leave DHCP enabled on the wireless router
- B
Assign the wireless router a LAN IP of 192.168.1.2, disable DHCP on it, and connect the ISP router to one of its LAN ports
- C
Change the wireless router's LAN subnet to 192.168.2.1/24 and connect the ISP router to its WAN port
- D
Enable port forwarding on the wireless router so wireless clients can reach the ISP router's network
Show answer and explanation
Correct answer: B
Explanation
When repurposing a consumer wireless router as a basic wireless access point, best practice is to disable features that create a separate Layer 3 boundary, such as DHCP and WAN-side routing/NAT, and connect it using a LAN port instead of the WAN port. Assigning it a static LAN IP within the existing subnet, such as 192.168.1.2, allows for future management without conflicting with the primary gateway at 192.168.1.1. This approach avoids double NAT, prevents competing DHCP servers, and keeps all clients on the same broadcast domain and subnet. This aligns with standard small-office network design practices and common vendor guidance for configuring a router in access point mode.
- A. Incorrect.
This would make the wireless router operate as a separate routed network behind its WAN interface, typically creating double NAT and a second DHCP scope. Clients connected to this device would likely receive addresses from the wireless router instead of the ISP router and would not remain on the same subnet as requested.
- B. Correct.
This is correct. Giving the wireless router a unique management IP in the existing subnet, disabling its DHCP service, and uplinking via a LAN-to-LAN connection effectively turns it into an access point/switch. In this setup, the ISP router remains the only device performing DHCP and routing, so all clients stay on the 192.168.1.0/24 network.
- C. Incorrect.
Changing the subnet and using the WAN port creates a separate network segment. Although this can work in some environments, it does not meet the requirement that all devices remain on the same subnet and obtain addresses from the ISP router.
- D. Incorrect.
Port forwarding is used to direct inbound traffic from one network interface to a specific internal host or service. It does not convert a router into a simple access point and does not solve the issue of keeping clients on the same subnet with centralized DHCP.