Subnet mask to host capacity: With subnet mask 255.255.255.224, what is the maximum number of IP host addresses available on a single subnet?

Introduction / Context:
Calculating usable hosts from a subnet mask is foundational for IP addressing design. The /27 mask (255.255.255.224) is a frequent example in certification exams.

Given Data / Assumptions:

• Subnet mask: 255.255.255.224 (/27)
• We want usable host addresses per subnet (excludes network and broadcast)

Concept / Approach:
Usable hosts per subnet = 2^(host_bits) - 2. For /27, there are 32 - 27 = 5 host bits.

Step-by-Step Solution:

Verification / Alternative check:
Block size of /27 is 32 addresses. Removing the network and broadcast leaves 30 hosts.

Why Other Options Are Wrong:

• 14/15/16: Correspond to smaller subnets (/28 or miscounting usable hosts).
• 62: That is typical of a /26 (64 addresses total minus 2).

Common Pitfalls:
Forgetting to subtract 2 for network and broadcast; mixing up /27 with /28 calculations.

Final Answer:
30