220-1101 Question 120
Single answerScopeA technician is configuring a small office router for a new network. The office uses the 192.168.10.0/24 subnet, and the router's DHCP service should automatically assign addresses to employee laptops while leaving addresses .1 through .49 available for infrastructure devices such as printers, access points, and servers. Which DHCP scope should the technician configure?
- A
192.168.10.1-192.168.10.49
- B
192.168.10.50-192.168.10.254
- C
192.168.10.0-192.168.10.255
- D
192.168.10.49-192.168.10.255
Show answer and explanation
Correct answer: B
Explanation
A DHCP scope defines the pool of IP addresses that a DHCP server can lease to clients. In a 192.168.10.0/24 network, the valid host range is 192.168.10.1 through 192.168.10.254. Because the organization wants to reserve 192.168.10.1 through 192.168.10.49 for static infrastructure devices, the correct scope for dynamically assigned client addresses begins at 192.168.10.50 and ends at 192.168.10.254. This reflects standard subnetting rules and common small-office best practices: reserve low addresses for infrastructure and assign a defined DHCP pool for user devices. These concepts align with common networking documentation and DHCP configuration guidance from major vendors such as Microsoft, Cisco, and SOHO router manufacturers.
- A. Incorrect.
This range is incorrect because it would assign addresses from .1 through .49 to DHCP clients. The scenario specifically states that .1 through .49 must remain available for statically assigned infrastructure devices such as printers, servers, and wireless access points.
- B. Correct.
This is correct. In a 192.168.10.0/24 network, usable host addresses are typically .1 through .254, with .0 as the network address and .255 as the broadcast address. Setting the DHCP scope from 192.168.10.50 to 192.168.10.254 allows client devices to receive automatic addresses while preserving .1 through .49 for static assignments.
- C. Incorrect.
This range is incorrect because .0 and .255 are not valid host addresses in a /24 subnet. .0 represents the network address, and .255 is the broadcast address. Including them in a DHCP scope would reflect a misunderstanding of IPv4 addressing.
- D. Incorrect.
This option is incorrect because it includes .49, which the scenario says must remain available for infrastructure devices. It also needlessly starts one address too early, reducing consistency with the stated reservation range.