100-150 Question 78
Single answerA network administrator needs to create four subnets from the IP address 192.168.10.0/24 for different departments. Each subnet should support up to 50 devices. Which subnet mask and slash notation should the administrator use to meet this requirement?
- A
255.255.255.224 (/27)
- B
255.255.255.192 (/26)
- C
255.255.255.240 (/28)
- D
255.255.255.248 (/29)
Show answer and explanation
Correct answer: B
Explanation
To support 50 devices per subnet, the administrator needs at least 50 usable IP addresses in each subnet. Using the subnet mask 255.255.255.192 (/26) creates subnets with 64 total IP addresses, of which 62 are usable for hosts. This meets the requirement while leaving room for growth. Smaller subnet masks like /27, /28, and /29 do not provide enough usable host addresses.
- A. Incorrect.
255.255.255.224 (/27) provides 32 IP addresses per subnet (30 usable for hosts), which is insufficient for 50 devices.
- B. Correct.
255.255.255.192 (/26) provides 64 IP addresses per subnet (62 usable for hosts), meeting the requirement for 50 devices and allowing room for growth.
- C. Incorrect.
255.255.255.240 (/28) provides only 16 IP addresses per subnet (14 usable for hosts), which is insufficient for 50 devices.
- D. Incorrect.
255.255.255.248 (/29) provides only 8 IP addresses per subnet (6 usable for hosts), which is far too few for 50 devices.