Under the historical IPv4 classful scheme, which address class provides the fewest usable host addresses per network?

Introduction / Context: Although modern networks use CIDR, many exams reference classful IPv4 addressing. Knowing the relative host capacities per class clarifies why classful addressing was wasteful.

Given Data / Assumptions:

• Class A: /8 networks.
• Class B: /16 networks.
• Class C: /24 networks.
• Class D and E are not used for ordinary unicast hosts.

Concept / Approach: Usable host addresses per network (ignoring modern VLSM/CIDR): Class A has roughly 16 million minus 2, Class B about 65,534, and Class C about 254. Therefore, among unicast classes A/B/C, Class C has the fewest hosts per network.

Step-by-Step Solution: Recall default masks: A=/8, B=/16, C=/24.Compute host counts: 2^(host bits) − 2.For /24: 2^8 − 2 = 254 usable hosts → fewest among A/B/C.

Verification / Alternative check: Compare: A (2^24 − 2), B (2^16 − 2), C (2^8 − 2). The ranking is clear: C has the smallest host pool.

Why Other Options Are Wrong: Class D/E: Not for general host assignment (multicast/experimental).

Class A/B: Far more hosts per network than Class C.

Common Pitfalls: Confusing “fewest networks” with “fewest hosts per network.” Class C has many networks but few hosts per network.

Final Answer: Class C