N10-005 Question #865: Real Exam Question with Answer & Explanation

The correct answer is C: 255.255.255.0. The subnet mask 255.255.255.0 (CIDR /24) creates a block of 256 addresses. Subtracting the network address (e.g., .0) and the broadcast address (e.g., .255) leaves 254 usable host addresses - exactly what the question asks for. By comparison: 255.0.0.0 (/8) yields ~16 million hos

Question

Which of the following subnet masks indicate a subnet with exactly 254 assignable IP addresses?

Options

A255.0.0.0
B255.255.0.0
C255.255.255.0
D255.255.255.254

Explanation

The subnet mask 255.255.255.0 (CIDR /24) creates a block of 256 addresses. Subtracting the network address (e.g., .0) and the broadcast address (e.g., .255) leaves 254 usable host addresses - exactly what the question asks for. By comparison: 255.0.0.0 (/8) yields ~16 million hosts, 255.255.0.0 (/16) yields ~65,000 hosts, and 255.255.255.254 (/31) is a point-to-point mask with 2 addresses and 0 usable hosts under traditional rules.

Community Discussion

No community discussion yet for this question.

Full N10-005 Practice