Which of the following is correct about a /27 address count?

• A. A /27 subnet has 16 addresses
• B. A /27 subnet has 32 addresses
• C. A /27 subnet has 64 addresses
• D. A /27 subnet has 128 addresses

Answer: (B)

The total number of IPv4 addresses in a subnet is 2^(32 minus the prefix length). For a /27, 32 − 27 = 5 host bits, so 2^5 = 32 addresses exist in the subnet. Of these, the network and broadcast addresses are typically not assignable to hosts, so usable hosts are 30, but the total address count remains 32. The other common prefixes give different totals (e.g., /26 has 64, /25 has 128, /28 has 16). So a /27 subnet indeed contains 32 addresses.