100-150 Question 86
Single answerA company is assigning IP addresses to devices on its network. They want to allocate an IP address to a web server with the subnet mask of /28. How many usable host addresses are available within this subnet, and how should they define the network and broadcast addresses?
- A
16 usable host addresses; the network address is the first IP in the range, and the broadcast address is the last.
- B
16 usable host addresses; the network address and broadcast address are excluded from the usable range.
- C
14 usable host addresses; the network address and broadcast address are excluded from the usable range.
- D
14 usable host addresses; all IPs in the subnet range are usable.
Show answer and explanation
Correct answer: C
Explanation
A /28 subnet provides 16 total IP addresses (2^4 = 16). The first IP address in the range is the network address, and the last IP address is the broadcast address. These two addresses cannot be assigned to hosts, leaving 14 usable addresses for devices on the network.
- A. Incorrect.
Incorrect: While a /28 subnet provides 16 total IP addresses, only 14 are usable because the network and broadcast addresses are reserved.
- B. Incorrect.
Incorrect: There are not 16 usable host addresses in a /28 subnet; the network and broadcast addresses reduce the usable count to 14.
- C. Correct.
Correct: A /28 subnet provides 16 total IP addresses. However, the network address (first IP) and broadcast address (last IP) are reserved, leaving 14 usable host addresses.
- D. Incorrect.
Incorrect: Not all IPs in the range are usable. In every subnet, the network and broadcast addresses are reserved.