A team is creating a new workload subnet in a spoke virtual network. The subnet must support 41 VM NICs, 2 internal load balancer frontend IP configurations, 3 private endpoint IPs, and 4 spare IPs for near-term growth. Azure reserves 5 IP addresses in every subnet. What is the smallest IPv4 subnet size that satisfies the requirement?

/27, because 32 total addresses are enough for a small workload subnet.

A /27 provides only 32 total addresses, which leaves 27 usable addresses after Azure reservations. That is far below the 50 assignable addresses required here.

/25, because 128 total addresses are required once private endpoints are included.

A /25 would work, but it is not the smallest valid choice. It provides far more usable addresses than the scenario requires, making it unnecessarily large.

/28, because 16 total addresses are sufficient when load balancers are used.

A /28 provides only 16 total addresses, leaving 11 usable after Azure reservations. That cannot support the requested number of NICs, frontend IPs, private endpoints, and growth.

What does this AZ-104 question test?

CIDR notation defines the prefix length.

What is the correct answer to this question?

The correct answer is: /26, because 64 total addresses provide enough usable IPs for the workload and growth. — The subnet must provide 41 VM NICs, 2 internal load balancer frontend IPs, 3 private endpoint addresses, and 4 spare addresses, for 50 assignable IPs total. Azure reserves 5 addresses in every subnet, so the subnet must contain at least 55 total addresses. The smallest standard IPv4 subnet that meets that threshold is /26, which provides 64 total addresses and 59 usable addresses. Why others are wrong: /27 and /28 are too small once Azure’s reserved addresses are deducted, so they cannot satisfy the required IP count. /25 would also work, but it is larger than necessary and therefore not the smallest valid subnet size. The key calculation is total assignable addresses plus Azure reservations, not just the number of resources you plan to deploy.

What should I do if I get this AZ-104 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.