200-301 Question 277
Single answerYou are configuring a network for a small office and are tasked with assigning IP addresses to 14 devices. You decide to use the 192.168.1.0/28 subnet. Which of the following statements is true about this network mask and its usability?
- A
The /28 subnet mask provides 16 total IP addresses, with 14 usable for hosts.
- B
The /28 subnet mask provides 14 total IP addresses, with 12 usable for hosts.
- C
The /28 subnet mask provides 16 total IP addresses, with 12 usable for hosts.
- D
The /28 subnet mask provides 16 total IP addresses, with 14 usable for hosts if the broadcast address is reused.
Show answer and explanation
Correct answer: C
Explanation
A /28 subnet mask corresponds to 255.255.255.240, which provides 16 total IP addresses (2^4 = 16). Out of these, 2 addresses are reserved: the network address (e.g., 192.168.1.0) and the broadcast address (e.g., 192.168.1.15). This leaves 14 usable host IP addresses (e.g., 192.168.1.1 to 192.168.1.14), making the /28 subnet suitable for assigning IP addresses to 14 devices in the office.
- A. Incorrect.
This option is incorrect. While the /28 subnet provides 16 total IP addresses, only 14 addresses are usable for hosts because 2 addresses (network and broadcast) are reserved.
- B. Incorrect.
This option is incorrect because a /28 subnet provides 16 total addresses, not 14. Only the usable host addresses are 12.
- C. Correct.
This option is correct. A /28 subnet provides 16 total IP addresses. Out of these, 2 are reserved (network and broadcast), leaving 14 usable host IPs.
- D. Incorrect.
This option is incorrect because reusing the broadcast address is not a valid practice in standard networking.