100-160 Question 74
Single answerA company has a network with the IP range 192.168.1.0/24 but needs to divide it into smaller subnets to improve network segmentation for different departments. Each department requires at least 30 usable IP addresses. Which subnet mask should the company use to achieve this while maintaining efficient address utilization?
- A
/26
- B
/27
- C
/28
- D
/25
Show answer and explanation
Correct answer: B
Explanation
The company needs 30 usable IP addresses per subnet. A /27 subnet mask provides exactly 30 usable IP addresses per subnet, making it the most efficient choice for this scenario. While larger subnet masks (such as /25 or /26) could also work, they would waste IP addresses unnecessarily and limit the number of subnets available.
- A. Incorrect.
A /26 subnet provides 64 total IP addresses (62 usable) per subnet, which is more than the 30 required. However, it creates fewer subnets, which may not be ideal for network segmentation.
- B. Correct.
A /27 subnet provides 32 total IP addresses (30 usable) per subnet, which perfectly meets the requirement of at least 30 usable addresses and allows for efficient segmentation.
- C. Incorrect.
A /28 subnet provides 16 total IP addresses (14 usable), which is insufficient to meet the requirement of at least 30 usable addresses.
- D. Incorrect.
A /25 subnet provides 128 total IP addresses (126 usable) per subnet, which far exceeds the requirement but is inefficient for segmentation as it wastes many IP addresses.